Patent Publication Number: US-2020278277-A1

Title: Device and method of staining an organic material on a slide

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a device and method of staining an organic material on at least one slide. 
     It applies, in particular, to the field of biomedical analyses, and more specifically in the field of hematology, bacteriology or histology. 
     STATE OF THE ART 
     Staining is a routine activity for medical analysis laboratories including physicians and veterinarians. It can be manual or automated. 
     In the hematology field, the operator smears a drop of blood on a glass slide to form a thin layer of blood cells. After drying, the smear is placed in contact with a colorant, or successively with several colorants, each being specific to a family of cells. The contact time of the cells with the set of colorants allows the intensity of the colorant to be adjusted. A cleaning swab is often necessary at the end of the staining cycle. This staining step is essential for identifying cells under a microscope. 
     In the bacteriology field, the operator deposits a portion of a sample on a glass slide and then it is heat fixed. The sample is then placed in contact with one or more colorants or decolorants in order to distinguish the element looked for. The samples are obtained, for example, from urine, pus or culture media. The two stains used more frequently are the one known as the “GRAM” stain, for distinguishing GRAM+ and GRAM− types of bacteria, and the stain for detecting tuberculosis. 
     The histology field is similar. The samples are obtained from human tissues. The most common stain is the one known as Papanicolaou, largely used in particular for vaginal smears. There are many colorants and alcohols. 
     No rigorous protocols for manual staining exist that could amount to reference procedures. Regardless of the field, the operator can choose to put the various colorants and rinsing liquids in different jars and then successively immerse his slides to be stained in the previously prepared jars. He can operate otherwise, by placing the slides to be stained on bars positioned over a sink and then depositing copious amounts of the various colorants and rinsing liquids using wash bottles, thus causing a spillage. 
     In all cases, the contact time with the various products determined by a protocol must be observed, thus requiring stopwatches or timers to be used. The slides must then be dried so they can be used under a microscope. 
     There is also a device for automatic staining by immersion. In this common embodiment for automatic staining by immersion, the slides are grouped together in a basket, generally with a capacity of 10 to 20 slides. The basket is taken in charge by a mechanism which enables it to be immersed successively in a plurality of tanks containing the various colorants and the rinsing liquid. An empty final tank equipped with a fan can be reserved for drying the slides at the end of the staining cycle. 
     In the hematology case, and according to the conventional methods, for example May-Grunwald Giemsa or Wright Giemsa, it is essential to dilute the Giemsa colorant just before use. 
     Regardless of the field, it is known that this type of staining leads to a reagent being contaminated by the previous one, resulting in a progressive degradation in the staining. The contamination of one slide by another (cells passing from one slide to another) remains possible because of the presence of different samples in the same baths. This is frequently considered an unacceptable risk in bacteriology. By and large, there is significant colorant consumption and waste production. 
     One variant of automatic staining by immersion consists of using a plurality of unitary staining dishes. These are successively filled with the various colorants or rinsing liquids. In this example of realization, the colorants are most often thrown away after use, which ensures high repeatability and constant quality for the coloration. The risk of risk of inter-sample contamination is eliminated. The consumption of colorants remains high. 
     There are also devices for automatic staining by capillarity, applied solely in the hematology field. They use the capillarity principle and use very few colorants. The staining is obtained from fast staining. The staining protocol is unique and not parameterizable. 
     Procedures for automatic staining by depositing liquid exist that reproduce manual coloration over the sink mentioned above. The slides to be stained are placed on a turntable. Each slide passes under a series of wash bottles and receive the colorant specified by the protocol. The slides are emptied by accelerating the turntable, and pre-dried in the same way. The risk of contamination between slides is eliminated, but the consumption of colorants, used in excess, is significant. Cleaning the bowl of the centrifuge isn&#39;t pleasant for the operator. 
     Finally, there is automatic spray staining. The slides are placed on a centrifuge rotor with the smear oriented towards the wall of the centrifuge, which is equipped with several nozzles that vaporize the selected colorant as the slide passes. The colorant is only used once. The major drawback of this technique is the risk of the spray nozzles, necessarily of a small diameter, being blocked. Special colorants had to be developed to overcome this major drawback. The maintenance and verification procedures must be complied with absolutely. 
     The staining of the slides in a horizontal position has the advantage of not requiring dishes or tanks to contain the various “fluids” to be put into contact with the cells, generally colorants and rinsing liquids. The state of the art shows that, in a horizontal situation, the fluids are deposited on the slide by spillage and therefore in excess. It is therefore necessary to have a collecting jar that has to be emptied and cleaned. The major drawbacks are the consumption of colorants, which is not optimized, with as direct consequence an increase in the volume of waste to be treated and, in the context of automation, the impossibility of properly transporting the slide. 
     SUBJECT OF THE INVENTION 
     The present invention aims to remedy all or part of these drawbacks. In particular, the present invention is aimed at having automation of the staining with a slide positioned in a horizontal position, to eliminate any risk of inter-sample contamination while using a limited amount of colorant, thereby reducing the production of waste. 
     To this end, according to a first aspect, the present invention relates to a device for staining an organic element on at least one slide, said slide defining an axis contained within the plane of the slide, the device being characterized in that it comprises:
         at least one slide support on which is positioned the slide holding the organic element;   at least one means for spreading a staining fluid and/or a rinsing fluid on the slide, which means is paired with a means for relative displacement in translation in relation to the slide and along the axis of said slide, the spreading means having a linear element extending along an axis perpendicular to the axis of the slide and supplied with spreading fluid; and   at least one suction means for suctioning the staining fluid and/or the rinsing fluid, said suction means being paired with a means for relative displacement in translation in relation to the slide along the axis of said slide.       

     Thanks to these provisions, the consumption of fluids is low, and therefore the generated waste to be treated by the laboratory is low. In addition, the device that is the subject of the present invention offers the possibility of mixing fluids directly on the slide and then homogenizing the mixture perfectly if necessary. Also, the device that is the subject of the present invention has no tanks or other containers to be cleaned. The small amount of fluid on the slide means it can be transported without spillage in the context of automation. The spreading means is able to carry out the distribution of fluid, its spreading and its possible homogenization. 
     Compared to capillary staining, the device that is the subject of the present invention is not limited to hematology with a single protocol and a single set of colorant usable. 
     Compared to automatic spray staining, the device that is the subject of the present invention is differentiated by the absence of pulverization, whose main drawbacks are the risk of the injection nozzles being blocked, which obliges the laboratories to use dedicated sets of colorants, and the need to clean the bowl of the centrifuge. 
     The device that is the subject of the present invention makes it possible to use a small amount of fluid, which is only used once to ensure staining with a constant and repeatable quality, the individual treatment of each slide eliminating the risk of contamination from one slide to another and the small amount of generated biological waste to be treated. 
     Compared to immersion stainings, the device that is the subject of the present invention enables individual treatment of each slide with colorants used a single time. This arrangement thus eliminates any risk of one colorant being contaminated by the previous one or one sample by another. 
     Compared to automatic staining by depositing colorant, the device that is the subject of the present invention is clearly differentiated by the small amount of colorants used and having no cleaning of a fluid collecting jar bowl. 
     Compared to immersion stainings in collective dishes, the device that is the subject of the present invention is clearly differentiated by the small amount of colorants used, the absence of risk of contamination between slides and the reduction in emissions. 
     Compared to immersion stainings in individual dishes, the device that is the subject of the present invention is clearly differentiated by the small amount of colorants used and the reduction in emissions. 
     In some embodiments, at least one suction means comprises a linear element extending along an axis perpendicular to the axis of the slide for carrying a suctioned fluid. 
     These embodiments make it possible to suction the liquids to be removed from the slide over the entire width of the slide. The speed of movement of the suction means over the slide, the suction force and the number of passages makes it possible to partially or totally remove the fluid present on the slide. 
     In some embodiments, the linear element of at least one spreading means is the linear element of at least one suction means. 
     The advantage of these embodiments is that they make it possible to limit the dimensions of the device. 
     In some embodiments, the suction means is positioned in succession to the spreading means, and the device comprises a means for controlling the spreading means and suction means simultaneously, creating a turbulent flow for cleaning the slide. 
     The advantage of these embodiments is to create a mechanical friction of a mixture of liquid and air cleaning the impurities of the organic element spread over the slide without detaching the cells contained in the organic element. 
     In some embodiments, at least one spreading means comprises two fluid supply means utilized simultaneously. 
     These embodiments make it possible for sensitive colorants needing to be applied immediately after mixing, for example Giemsa, to be mixed directly on the slide. The liquids are therefore mixed on the slide by the two supply means. 
     In some embodiments, the spreading means comprises a means for mixing fluids coming from the supply means. 
     These embodiments make it possible to ensure that the fluids coming from the supply means are mixed. 
     In some embodiments, for hematology, in which the organic element is an organic liquid, it also comprises: 
     at least one dispenser of at least one drop of organic liquid on the slide placed on the support; 
     at least one smearing means perpendicular to the axis of the slide smearing the organic liquid in the axis of the slide; and 
     at least one means for lifting a deactivated smearing means in order to lower the smearing means above the slide to come into contact with the drop of organic liquid, which migrates by capillarity over the smearing means perpendicular to the axis of the slide, the drop being smeared by relative displacement between the smearing means and the slide. 
     Thanks to these provisions, the device that is the subject of the present invention performs the smear and the staining. The slide can therefore be treated completely by the device. 
     In some embodiments, the device that is the subject of the present invention comprises a tank for cleaning the smearing means, into which the smearing means is lowered to be cleaned. 
     These embodiments make it possible to clean the smearing means between two juxtaposed slides, for example. 
     In some embodiments, the volume of a spread staining fluid and/or rinsing fluid is between 0.4 milliliters and 1 milliliter for a rectangular slide of 25 millimeters by 75 millimeters. 
     Thanks to these provisions, a very small volume of liquid is spread over the slide, and therefore there is no spillage of the staining fluid and/or rinsing fluid. The displacement of the slide is therefore also facilitated. In addition, the amount of waste is limited. 
     In some embodiments, the device that is the subject of the present invention comprises at least two juxtaposed slide supports and means for relative displacement between the staining device and each slide, The displacement means being configured to position the staining device along the axis of each slide in succession. 
     The advantage of these embodiments is to automate the staining of several successive slides. 
     According to a second aspect, the present invention relates to a method of staining an organic material on at least one slide, said slide defining an axis contained within the plane of the slide, the method being characterized in that it comprises the following steps: 
     positioning at least one slide holding the organic element on at least one slide support; 
     spreading a staining fluid and/or a rinsing fluid on the slide by means of a linear element along an axis perpendicular to the axis of the slide; and 
     suctioning the staining fluid and/or a rinsing fluid by means of a linear element along an axis perpendicular to the axis of the slide. 
     In some embodiments, the method that is the subject of the present invention also comprises the following steps: 
     distributing at least one drop of organic liquid on the slide; 
     lowering a smearing means above the slide; 
     smearing the organic liquid along the axis of the slide by displacement between the smearing means and the slide; and 
     lifting the smearing means. 
     As the particular aims, advantages and features of the method that is the subject of the present invention are similar to those of the device that is the subject of the present invention, they are not repeated here. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other advantages, aims and particular features of the invention will become apparent from the non-limiting description that follows of at least one particular embodiment of the device and method that are the subjects of the present invention, with reference to drawings included in an appendix, wherein: 
         FIG. 1  represents, schematically and in a side view, a first particular embodiment of the device that is the subject of the present invention; 
         FIG. 2  represents, schematically and in perspective, the first particular embodiment of the device that is the subject of the present invention; 
         FIG. 3  represents, schematically and in a front view, the first particular embodiment of the device that is the subject of this invention; 
         FIG. 4  represents, schematically and in a side view, a second particular embodiment of the device that is the subject of this invention; 
         FIG. 5  represents, schematically and in a side view, a third particular embodiment of the device that is the subject of the present invention; 
         FIG. 6  represents, schematically and in the form of a logical diagram, a particular series of steps of the method that is the subject of the present invention; 
         FIG. 7  represents, schematically and in a side view, a first particular embodiment of a cleaning tank; and 
         FIG. 8  represents, schematically and in a front view, the first particular embodiment of a cleaning tank. 
     
    
    
     DESCRIPTION OF EXAMPLES OF REALIZATION OF THE INVENTION 
     The present description is given in a non-limiting way, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous way. In addition, each parameter of an example of realization can be utilized independently from the other parameters of said example of realization. 
     The meaning of the following terms is noted here: 
     “juxtaposed” means elements are placed side by side; 
     “in succession” and “successively” means one after the other; and 
     “linear” refers to the continuous aspect of a line. 
     It is now noted that the figures are not to scale. 
       FIGS. 1 and 3  show several schematic views of an embodiment of the device  10  that is the subject of the present invention. The device  10  for staining an organic element on at least one slide  105  comprises a slide  105  support (not shown) on which is positioned the slide  105 . The slide  105  defines an axis  110  contained within the plane of the slide  105 . 
     For clarity, here, a slide for biomedical analyses is a thin, flat, rectangular piece of glass used as a support for medical analyses. The axis of the slide  105  is the axis passing via the middle of the rectangle of the slide  105  and parallel to the largest side of the rectangle. It is also noted that an organic element is body tissue, blood or any other sample taken from a living being. 
     The slide  105  support enables the slide to be placed in a horizontal position. In some embodiments, the slide  105  support keeps the slide in a horizontal position. The slide  105  support can be any means known to the person skilled in the art, fixed relative to the device  10 . 
     In some embodiments, the organic element is positioned on the slide  105  before the slide  105  is placed on the support. 
     The device  10  also comprises a means  115  for spreading a staining fluid and/or a rinsing fluid on the slide  105 , paired with a means  175  for relative displacement in translation in relation to the slide  105  along the axis  110  of the slide  105 , the spreading means  115  having a linear element  120  extending along an axis  160  perpendicular to the axis  110  of the slide  105  and supplied with spreading fluid. 
     In some embodiments, the linear element  120  has at least two channels emerging close to the slide. The distance between the outlet of the channels  120  and the slide  105  is less than five millimeters. The channels are parallel to each other close to the slide such that each channel  120  delivers a similar amount of liquid. Preferably, the distance between the outlet of the channels  120  and the slide  105  is 0.3 millimeters. 
     In some embodiments, the linear element  120  has a slot. A slot is an aperture whose shape is contained within a rectangle and where the ratio of the large to small sides is greater than two. Preferably, the slot is rectangular and the dimension of the small side is equal to the dimension of a channel. 
     The linear element  120  is supplied by tubes  125 ,  130 ,  135  for delivering fluids, connected to tanks (not shown), each containing staining or rinsing fluid. A pump (not shown) handles the supply of fluid from the tank. 
     In the embodiment shown in  FIGS. 1 to 3 , the tube  135  is connected to a tank containing a rinsing fluid, and the tubes  125  and  130  are connected to tanks containing staining fluids. Preferably, all the tubes,  125 ,  130  and  135 , emerge in the spreading means  115  in the middle of the distance between the channels  120  farthest apart, or in the middle of the slot, for example. 
     Preferably, the volume of a spread staining fluid and/or rinsing fluid is between 0.4 milliliters and 1 milliliter for a rectangular slide  105  of 25 millimeters by 75 millimeters. 
     In some embodiments, the spreading means  115  comprises two fluid supply means utilized simultaneously. A supply means comprises at least one tube,  125 ,  130  or  135 , one pump and one tank. In these embodiments, two staining fluids reacting together to stain the organic fluid are mixed and delivered simultaneously. The tubes,  125  and  130 , are supplied simultaneously with staining fluid. For example, one staining fluid is the Giemsa staining fluid and one staining fluid is a Giemsa diluent. 
     The supply means are activated simultaneously, for example after the command issued by the control means, and the two staining fluids are mixed at the entry of the channels  120  into the spreading means  115 . 
     In some embodiments, the spreading means  115  comprises a means for mixing fluids coming from the supply means. The mixing means can be a screw or mixer or, when the spreading means and the suction means are combined, a spreading of the fluids mixed at the entry of the channels and then at least one suctioning of these fluids and another spreading of the suctioned fluids. More generally, the mixing means is configured to create a turbulent flow between the fluids to homogenize the mixture of the fluids. 
     In some embodiments, at least one tube  130  is attached to the spreading means  115  by tabs in the form of a deformable hook on a casing of the device  10 . In some embodiments, at least one tube  125  is attached to the spreading means  115  by passing through the casing of the device  10 . 
     The displacement means  175  can be a rack and a corresponding toothed wheel, or a pulley and belt assembly, in the axis  110  of the slide  105 . Control of the displacement means  175  can be performed by a stepping motor. 
     The device  10  comprises a suction means  115  for suctioning the staining fluid and/or a rinsing fluid, paired with a means  175  for relative displacement in translation in relation to each slide  105  along the axis  110  of said slide  105 . 
     Preferably, the suction means  115  comprises a linear element extending along an axis  160  perpendicular to the axis  110  of the slide  105  for carrying a suctioned fluid. 
     In some embodiments, the linear element  120  has at least two channels emerging close to the slide  105 . The distance between the outlet of the channels  120  and the slide  105  is less than five millimeters. The channels are parallel to each other close to the slide such that each channel  120  suctions up a similar amount of liquid. Preferably, the distance between the outlet of the channels  120  and the slide  105  is 0.3 millimeters. 
     In some embodiments, the linear element  120  has a slot. A slot is an aperture whose shape is contained within a rectangle and where the ratio of the large to small sides is greater than two. Preferably, the slot is rectangular and the dimension of the small side is equal to the dimension of a channel. 
     The linear element  120  is connected to a suction tube  140  for suctioning waste fluids connected to a waste tank. A pump (not shown), for example managed by a control means, handles the suctioning up of fluids on a slide  105  towards the waste tank. Preferably, the tube  140  emerges in the suction means  115  in the middle of the distance between the channels  120  farthest apart, or in the middle of the slot, for example. 
     In some embodiments, the tube  140  is attached to the suction means  115  by tabs in the form of a deformable hook on a casing of the device  10 . In some embodiments, the tube  140  is attached to the suction means  115  by passing through the casing of the device  10 . 
     The displacement means  175  can be a rack and a corresponding toothed wheel, or a pulley and belt assembly, in the axis  110  of the slide  105 . Control of the displacement means  175  can be performed by a stepping motor. 
     Preferably, the linear element  120  of the spreading means  115  is the linear element  120  of the suction means  115 . This embodiment is represented in  FIG. 1 . In some embodiments, all the tubes,  125 ,  130 ,  135  and  140 , emerge in the spreading means  115  in the middle of the distance between the channels  120  farthest apart, or in the middle of the slot, for example. 
     In some embodiments not shown in  FIGS. 1 to 3 , the suction means  115  is positioned in succession to the spreading means  115  along the axis  110  of the slide  105 , the simultaneous utilization of the spreading means  115  and the suction means  115  creating a turbulent flow for cleaning the slide  105 . In other words, the suction means is positioned in succession to the spreading means, and the device comprises a means for controlling the spreading means and suction means simultaneously, creating a turbulent flow for cleaning the slide. In these embodiments, a cleaning liquid is ejected by the spreading means  115  and immediately suctioned up by the suction means  115 . 
     The suctioning by the suction means  115  simultaneously suctions up air and the liquid ejected, thus creating a mechanical friction between the cleaning liquid and the stained organic element. The impurities in the stained organic element are detached from the stained organic element and suctioned up with the cleaning liquid. The stained cells are held in place. The impurities are, for example, colorant precipitates formed during the spreading of the colorant. 
     Preferably, the distance between the linear element  120  of the spreading means  115  and the linear element  120  of the suction means  115  is less than two millimeters. And the linear elements  120  are parallel. 
     In some embodiments, for hematology, the device  10  also comprises: 
     at least one dispenser  170  of at least one drop of organic liquid on the slide placed on the support; 
     at least one smearing means  145  perpendicular to the axis  110  of the slide  105  smearing the organic liquid in the axis  110  of the slide  105 ; and 
     at least one means  150  for lifting a deactivated smearing means  145  in order to lower the smearing means  145  above the slide  105  to come into contact with the drop of organic liquid, which migrates by capillarity over the smearing means perpendicular to the axis  110  of the slide  105 , the drop being smeared by relative displacement between the smearing means  145  and the slide  105 . 
     The device  10  also comprises a distributor  170  distributing at least one drop of organic liquid on the slide  105 . The distributor  170  can comprise a means for setting the organic liquid in rotation. 
     The smearing means  145  is preferably a rectangular slide in which the dimension of the smallest side is less than or equal to the dimension of the slide  105  perpendicular to the axis  110  of the slide  105 . The slide of the smearing means  145  is inserted into a support comprising one portion made of a material sensitive to a magnetic force juxtaposed with a portion made of glass. The smearing means  145  comprises a means for setting in rotation relative to the casing of the device  10 . The axis of rotation of the means for setting the smearing means  145  in rotation is perpendicular to the axis  110  of the slide  105 . The axis of rotation is located at the junction of the portion made of a material sensitive to a magnetic force and the portion made of glass. 
     The lifting means  150  is an electromagnet located above the portion made of a material sensitive to a magnetic force. The electromagnet, once released, frees the portion of the slide of the smearing means  145  made of a material sensitive to a magnetic force, which causes the portion made of glass to be lowered towards the slide  105 . The pressure exerted on the slide  105  by the smearing means  145  is provided by at least one spring. 
     Only the line segment  146  at the extremity of the portion of the slide made of glass is in contact with the slide  105 . In this way, a drop of organic liquid placed on the axis  110  of the slide  105  is spread over the line segment  146  by capillarity when the line segment  146  comes into contact with the drop. Then, the drop spread in this way over the line segment  146  is driven by displacement of the lowered smearing means  145  along the axis  110  of the slide  105 , and therefore smeared by capillarity. The line segment  146  forms an angle with the slide  105  such that only one edge of the parallelepiped formed by the slide of the smearing means  145  is in contact with the slide  105 . 
     The displacement can be performed by a displacement means  175 . The displacement means  175  can be a rack and a corresponding toothed wheel, or a pulley and belt assembly, in the axis  110  of the slide  105 . Control of the displacement means  175  can be performed by a stepping motor. 
     In some embodiments, the spreading means  145  can be a slide lowered by translation. In some embodiments, the lifting means  150  can be any means for setting in rotation or in translation of an element known to the person skilled in the art. 
     In some embodiments, the device  10  comprises a tank  70  for cleaning the smearing means  145 , into which the smearing means  145  is lowered to be cleaned. The cleaning tank is placed in the axis  110  of the slide  105 . Once the drop has been smeared, the smearing means  145  is lifted and lowered again into the cleaning tank  70  to prevent any contamination of one organic fluid sample by another. 
     The cleaning tank  70  has the shape of a sloping chamfer or side of a triangle  705  and comprises, on one surface, a spreading means  710  and a suction means  710  similar to those described above, creating a turbulent flow as indicated above. The fluid used is an isotonic diluent. In other embodiments, the isotonic fluid is spread in the cleaning tank  70  and the cleaning is performed by immersion of the smearing means  145 . 
     Preferably, the cleaning tank  70  comprises a drain  715  for cleaning fluid. 
     In  FIGS. 1 to 3 , the embodiment of the device  10  shown comprises the distributor at least one drop of organic liquid, the spreading means  115  and the suction means  115  whose channels  120  are combined, the lifting means  150  and the smearing means  145  grouped together in a casing. The means  175  for displacing the spreading means, suction means  115  and smearing means  145  are a single displacement means  175 . The device  10 , of  FIGS. 1 to 3 , is mounted on a chassis (not shown) comprising a slide  105  support fixed relative to the chassis. The displacement means  175  displace the device  10  relative to the chassis, along the axis  110  of said slide  105 . 
     In other embodiments, the device  10  is fixed relative to the chassis and each slide  105  is mobile relative to the chassis. The displacement means  175  displaces each slide  105  relative to the chassis, along the axis  110  of said slide  105 . 
     These embodiments make it possible to have a compact device  10  particularly suited to analysis laboratories carrying out a limited number of analyses every day. 
     The embodiments of the staining device,  20  and  30 , shown in  FIGS. 4 and 5 , the device,  20  or  30 , comprises at least two juxtaposed supports,  205  or  310 , for slides  105  and means,  210  or  315 , for relative displacement between the staining device and each slide, configured to position the staining device  10  along the axis  110  of each slide  105  in succession. 
     In  FIG. 4 , each slide support  205  keeps a slide  105  in a horizontal position in a rack  220 . The axes  110  of the slides  105  are parallel. The displacement means  210  is a rack and a corresponding means or a pulley and belt assembly, in an axis perpendicular to the axis  215  of each slide  105 . The displacement means  210  can be any means for displacement in translation known to the person skilled in the art. Control of the displacement means  210  can be performed by a stepping motor. In  FIG. 4 , the device  10  corresponds to the device  10  shown in  FIGS. 1 to 3 . 
     The device  10  performs a first pass for smearing the smear and several other passes, spaced by lengths of time controlled, for example by a control means, as a function of the contact times of the colorants, for the different colorants and rinse. In some embodiments, the device  10  also has means for homogenizing the tubes of blood, piercing the plug, taking a sample of the blood and forming a drop. 
       FIG. 5  shows a third particular embodiment of the device  30  that is the subject of the present invention. In the device  30 , the various means carrying out the various functions are separated into at least two different modules of device  10 . All the modules form the device that is the subject of the present invention. 
     In the embodiment shown, the modules are arranged in a circular arc and each slide is displaced relative to the modules along an axis corresponding to the radius of the circular arc that corresponds to a position of the axis  110  of a slide  105 . The device  30  comprises several slide supports  310 , and the slide supports  310  are arranged in a circle on a carousel having a circular disk shape  305 . For clarity, here, a carousel is an appliance intended for transporting, in a closed circuit, loads, objects or goods. 
     The slides  105  are loaded onto the carousel  305  when the slide support  310  is situated at a first location, represented by an arrow towards the carousel  305  on the left of  FIG. 5 . The slide  105  is unloaded from the carousel  305  in a location other than the loading location, and before a complete rotation of the carousel  305 . The loading and unloading of the slides can be automated. 
     The axis  110  of each slide  105  corresponds to a radius of the carousel. The circular arc between the axis  110  of each slide  105  is identical. The supports  310  for slide  105  are spread evenly on an upper surface of the carousel  305 . 
     The carousel is considered to comprise n locations juxtaposed or side by side on the circular arc, each location forming a different radius. A module of the device  10  can be positioned opposite a location. A module can comprise: 
     a distributor  170  distributing at least one drop of organic liquid on a slide  105 ; 
     a means  115  for spreading a staining fluid; 
     a means  115  for spreading a rinsing fluid; 
     a spreading means  115  comprising two staining fluid supply means utilized simultaneously; 
     a suction means  115  different from each spreading means; 
     a spreading means  115  whose channels  120  are combined with the channels of a suction means  115 ; 
     a smearing means  145  and a lifting means  150 ; 
     a spreading means and a suction means positioned in succession, and the device comprises a means for controlling the spreading means and suction means simultaneously, creating a turbulent flow for cleaning the slide; 
     or a combination of the above means. 
     An example of the embodiment shown in  FIG. 5  is described below. 
     The loading position contains a module comprising a distributor  170 . The module in the next position comprises a smearing means  145  and a lifting means  150 . The following module comprises a means  115  for spreading a staining fluid. The very next module comprises a means  115  for suctioning a staining fluid. The next module comprises a means  115  for spreading two staining fluids simultaneously. The following module comprises a means  115  for spreading a rinsing fluid. Lastly, the final module before unloading comprises a module  115  for suctioning the rinsing fluid. 
     The unloading location is shown by an arrow on the right of the device  30  of  FIG. 5 . The rotation of the carousel  305  can be punctuated by drying phases of a predetermined length. Preferably, to control the drying time for each staining phase, each spreading means  115  comprises channels  120  combined with a suction means. The suction means  115  of different modules can therefore be activated at different times depending on the drying or waiting times required for each colorant before a rotation of the carousel  305 . 
     The carousel  305  can be paced to change position at a fixed frequency. The frequency can be between 30 and 60 seconds. The various modules are distributed on the periphery of the carousel  305 , which comprises a number of locations. Preferably, the carousel comprises more than ten locations. Preferably, the carousel  305  comprises forty locations. 
     For example, in some embodiments: a first slide  105  is positioned on the carousel  305 , the carousel  305  turns one position which makes it possible to place it in the smearing position and, possibly, to deposit another slide. The smear must dry several minutes before receiving a first colorant. Therefore the first staining module must be not be next but rather several positions further, based on the desired rotation rate and drying time. 
     In some embodiments, the device  30  is accompanied by a module comprising a conveyor in translation on which are positioned slides  105  along its axis  110 . Each slide  105  is first positioned under a distributor, then under a smearing means  145 , equipped with a lifting means  150 , which is lowered while a drop is deposited onto a preceding slide. The translation of the conveyor thus spreads the organic liquid on the slide  105 . 
     In this embodiment, the slides  105  are loaded on the carousel  305  impregnated with the dried organic liquid. 
       FIG. 6  shows a series of steps of method  60  for staining an organic material on at least one slide  105 , said slide  105  defining an axis  110  contained within the plane of the slide  105 , said method comprising the following steps: 
     positioning  61  at least one slide  105  on at least one support,  205  or  310 , of the slide  105 ; 
     spreading  66  a staining fluid and/or a rinsing fluid on the slide  105  by means of a linear element  120  along an axis perpendicular to the axis  110  of the slide  105 ; and 
     suctioning  67  the staining fluid and/or a rinsing fluid by means of a linear element  120  along an axis  160  perpendicular to the axis  110  of the slide  105 . 
     In some embodiments, the method  60  also comprises the following steps: 
     distributing  62  at least one drop of organic liquid on the slide  105 ; 
     lowering  63  a smearing means  145  above the slide  105 ; 
     smearing  64  the organic liquid along the axis  110  of the slide  105  by displacement between the smearing means  145  and the slide  105 ; and 
     lifting  65  the smearing means  145 . 
     Preferably, the method  60  comprises a step of drying the organic liquid and/or a staining fluid. The drying step preferably occurs after each smearing step and after each spreading step. The drying step is shown by a stopwatch in  FIG. 6 . 
     The positioning step  61  can be manual, for example on a support  205  of  FIG. 2 , or automated, for example on a support  310  of device  30 . 
     The distribution step  62  is carried out by a distributor  170 . Preferably, the drop is distributed on the axis  110  of the slide  105 . Preferably, the drop is distributed in an area of the slide  105  around the middle of the slide  105  along the axis  110  and whose dimension along the axis  110  of the slide  105  is less than seventy-five percent of the dimension of the slide  105 . A drop has a volume of the order of five microliters. 
     The lowering step  63  is utilized by the lifting means  150 . The smearing step  64  is performed by the lowered smearing means  145 . The displacement of the smearing means  64  along the axis of the slide  105  is sufficient to smear the organic liquid by capillarity. The lifting step  65  is performed by activating the lifting means  150 . The smearing means  145  is lifted to avoid interfering with the staining during the spreading step  66 . 
     The lowering step  66  is utilized by the spreading means  115 . During the spreading step  66 , a staining fluid and/or a rinsing fluid can be spread. In some embodiments, the method  60  also comprises a step of supplying at least two fluids during the spreading step  66 . The spreading  66  is therefore a simultaneous spreading of two staining fluids. The spreading step  66  can be preceded by a step of mixing two staining fluids. The spreading step  66  can be utilized simultaneously with a suction step  67 . 
     The suction step  67  is utilized by the suction means  67 . 
     The method  60  can comprise several repetitions of a spreading step  66  and suction step  67  pair. 
     In some embodiments, the method  60  also comprises a step of relative displacement between, a spreading step  66 , a smearing step  64  and/or a suction step  67 , along the axis  110  of one slide  105  to the axis  110  of another slide  105 . Such relative displacements are described with reference to  FIGS. 4 and 5 , for example. 
     In some embodiments, the method  60  comprises the following prior steps: 
     mixing tubes of organic liquid by rotation; and 
     during the positioning step  61 :
         piercing a plug of the tube by a needle;   extracting a predefined amount of organic liquid;   forming a drop of organic liquid at the end of a thin tube, known as a “pipette”, contained in the dispenser and emerging close to the slide.       

     In some embodiments, the method  60  comprises a step of cleaning the smearing means  145  by contact with the cleaning liquid. 
     Preferably, the method is utilized by one of the embodiments  10 ,  20  or  30  described above. 
     In the embodiments shown in  FIGS. 1 to 5 , a slide  105  is placed in a slide support  205  during the positioning step  61 . Then a drop of organic liquid is distributed on the slide  105  by the distribution means during a distribution step  62 . The line segment  146  of the smearing means  145  is placed opposite the drop then lowered during the lowering step  63 . The lowering of the smearing means  145  by the lifting means  150  spreads the drop on the slide  105  by capillarity. Then the lowered smearing means  145  is displaced along the axis  110  of the slide  105  according to the smearing step  64 . The smearing means  145  is then lifted during a lifting step. 
     The device  10  of a module of the device  10  or the slide  105  is displaced to put the spreading means  115  opposite the location where the drop of organic liquid has been deposited. The displacement can be along the axis of the slide  105  to a predefined location or under a different module. The spreading means  115  is supplied with at least one staining liquid and the device  10  is displaced along the axis  110  of the slide  105  in the same direction as the smearing direction when the staining liquid is injected and emerges from the linear element  120  during the spreading step  66 . 
     Then, the device  10  of a module of the device  10  or the slide  105  is displaced to put the suction means  115  opposite the location where the drop of organic liquid has been deposited. The displacement can be along the axis of the slide  105  to a predefined location or under a different module. The suction means  115  is put into operation and the device  10  is displaced along the axis  110  of the slide  105  in the same direction as the smearing direction when the staining liquid is suctioned by a linear element  120  after a predefined length of time based on the staining liquid during the suction step  67 . 
     The spreading step  66  and suction step  67  can be repeated several times with several different staining or rinsing fluids. The staining fluids can be mixed. 
     Preferably, the method  60  utilizes the functions of the device  10 ,  20  or  30 . 
     As can be understood from reading the present description, the following means may also be called: 
     for a spreading means: a distributer, a distribution circuit or a spreader; 
     for a suction means: a suction unit, a suction circuit or a suction pump; 
     for a displacement means: a displacement motor; 
     for a mixing means: a blender or a mixer; 
     for a smearing means: a spreader or an applicator; 
     for a lifting means: lifter or hoist; 
     for a control means: controller; 
     for a means for setting in rotation: a rotation motor; and 
     for a supply means: a supply circuit or a supply pump.