The daily morning journal and courier., 1898-08-11

l aSI lllC pGt oL ptttSs Il ISoG SAlleh llstN's
 not been found in all forms of bacteria
 which move, but their presence is in ferred, since every advance in the
 study of motils forms increases the
 number of bacteria which arc seen to possess them.
 These light-producing bacteria are known as photo-bacteria, and so far
 some half-dozen varieties have been
 distinguished and named. The names
 in such cases are usually either given
 from the locality of their appearance
 thus, photo bacterim Balticum, found
 in the Baltic), from their discoverer
 (for example, photo o-bacterium Fische-
 ri, after Professor Fischer), or from
 some striking attribute (to wit, photo-
 bacterium phosphosescens, the com
 monest light-giving species).
 That they lie at the bottom of the
 matter-that phosrescence ia due to
 their presence-has been and can be
 proved in several pretty ways. It is
 not sufficient, of course, that we should
 always detect them in any examination
 of luminous water; to prove that
 they are the cause of light we must be
 able to procure luminosity by intro ducing them into water that did not
 previously show this quality, and this
 can be done thus:
 l Place a few of these organisms into
 sea-water or broth prepared from fish,
 and keep at a suitable temperature; l they can then be spread and develop | phosphorescence appears, so that a re-
 moval of the vessel into another room
 shows unmistakably the glow of the
 familiar light. It only appears, how
 ever, at the surface of the liquid, where I the oxygen of the air has free access to
 the bacteria; if, for experiments sake,
 the supply of fresh air be cut off-that
 is, if no oxygen be allowed to come near l them-then the little colony of bacteria
 loses it's fascinating power and remains i dull and shorn of it's glory. But re-
 store the air, and the microbes again
 recover their normal corollary. There
 is a tale told that a woman whose hus-
 band made bacteria his study took | leaf out of his book, and cultivated l these bacteria on gelatine in such a
 way that as they developed they shone l out the message, 'Hommage a M. Pas
 teur." The shining letters were then
 photographed and the picture sent to | the great bacteriologist, thus conveying
 in graceful form the warm appreciation
 in which he was held by those follow l ing in his steps.
 | The explanation, too, of the luminous
 shoals of fish is now made plain, and
 we can apparently get fiery herrings'
 at will. No longer are we to believe that the herrings themselves, by the
 exercise of some marvellous power, or l by the excretion of an extraordinary | substance, give rise to the striking lu-
 minosity, but rather that their bright
 ness is due to myriads of these infini- | tesimal bodies, which cling to their sur- | faces and invest them in a coat of shin | ing light, Thus, if some herrings new l ly caught, and with the sea-water still | fresh on them be placed on one plate l and covered down with another and l then put into suitable temperature l and left for day and a night, glints of | light can, at the end of the time, be de- tected at various points on their bodies when they are examined in dark room. If they are yet again put away | for another twenty-four hours, the points of light spread until the whole l of the fish are enveloped in beautiful l bluish glow. The light is then at it's | best and gradually fades away as the fish putrefies and the sea-water dries
 up. If little of the light-giving mat
 ter be scrapep off the skins of the her. rings and examined under the micro- scope, it shows itself to be nothing but | colonies or collections of bacteria, all i living at great pace, dividing, multi
 plying and developing at a tremendous
 rate Each member of colony is nor I ,,p1Ir EieI, i,, cLn but iy, stage of reproduction it is continually l elongating into long ellipse, a con- striction appears at the middle, and it
 divides into two. Each of these two in
 their turn elongate, become constricted, and divide. nd so it goes on, the pro l cess being often so rapid that short
 chains are formed, the various portions l being unable to break away in time.
 The particular bacterium which affects herrings and cod is remarkable for it's
 great luminosity; in fact, it exceeds all
 other species in this quality.
 1 It is a curious fact that the addition Of little sugar to the liquid or the l gelatine on which these phosphorescent 1 bacteria are being cultivated increases very much their power of producing light; the sugar must, however, be used
 with great moderation, as too much of
 it has contrary effect and checks the l luminosity altogether. The reason for | this is that nearly all this class of bac- l teria require carbon as nourishment if they are to develop to their highest 1 powers. Like much of the food we eat, | it is not essential to them; they can | manage very well without it, but they | are all the better for having it. Now, sugar is very largely composed of car l bon; hence the good results which fol- | low it's presence. Glycerine, which is
 of similar composition, will do almost as well; from both bacteria can easily | withdraw carbon. Two photo bacteria | have, however, been oberved which are somewhat differently constituted; one | is found round the West Indies, and the other in the North Sea, and neither ap-
 parently requires sugar or glycerine in any form-in fact, either of these sub | stances, even in the smallest quantity, appears to be directly injurious. But why this should be so 1t is not easy to define.
 A Dutchman named Beyerinck has 1 lately made special study of these photo-bacteria, and has eperimented with them in a great number of ways, | to determine, If possible, why they cb bpI1I5 tlt,S Tod ,J l