On some Appearances of the Red Blood-Corpuscles of Man and other Vertebrata
Authors: Dowdeswell G. F. 
Published: April 2021

Some time since, in examining the action of septic matter, I observed that when blood of man or the dog was treated on the warm stage of the microscope with an aqueous extract of putrid muscle, the red corpuscles shortly exhibited a curious phenomenon, throwing out from their surfaces numerous processes, which, in some cases formed a rosary of minute beads, in others fine undivided filaments, generally terminating in one or more droplets, and assuming a bifurcated or racemose appearance; they were of very variable size and form, from mere diminutive globules or protuberances on its surface up to five or six times in length the diameter of the corpuscle. These processes were evidently contractile, sometimes, from a considerable length, retracting suddenly into a globule, or being withdrawn entirely into the substance of the parent corpuscle; the detached particles, too, would coalesce into one larger globule. After a time, varying, according to circumstances, from a few minutes up to half an hour or so, they all became detached, forming a number of small spherical bodies of various size, undistinguishable from Micrococci; or short slender filaments, identically similar in appearance to Bacteria or Vibrios, and in incessant molecular movement swarmed over the field of view. About the same time, usually, the hull or stroma of the red corpuscles became colourless and difficult to distinguish, for all the reagents with which I obtained these processes dissolve out the hæmoglobin. In the finer filaments and minute globules any colouration is difficult to distinguish clearly, but when these coalesce into a larger body the colour becomes apparent, and it is most evident in the large processes which are formed in the blood of the frog, under the action of a 5-per cent, solution of ammonium chromate in the cold. When the colouring matter of the red corpuscles is dissolved out, and they disappear, the processes are also lost to sight; but upon treatment of the preparation with magenta or other staining fluid, both the hull of the red corpuscles and the processes too, become stained, and again apparent. On first observing this phenomenon I was in doubt whether it was to be regarded as a physiological and vital process, or merely as a physical one. Shortly afterwards Francis Darwin’s paper on the “Protoplasmic Filaments of the Teasel”1 appeared, and it seemed to me that there must be an intimate connection between the two phenomena, so essentially similar in character. I then instituted a series of experiments with solutions of different salts and various reagents, under different conditions, with a view to ascertain the laws which regulate these appearances. I subsequently found that the same processes in the red corpuscles of the blood of man had been described and figured some years previously by Dr. William Addison, F.R.S.1 The results I obtained myself agreed in the main with those described by him. It is sufficient here to mention that I found they occurred most readily, in the blood of mammals, when treated with a mixture of one part of pale sherry wine and one part of a 10-per cent, solution of sod. sulph., at a temperature of about 98° Fahr., or somewhat lower. The sp. gr. of this mixture is about 1·008, and its reaction acid; on neutralisation it fails to produce any processes from the red corpuscles. In an aqueous solution of sugar 2’5 per cent. sod. sulph. 10 per cent., alch. 15 per cent., and ac. acet. 1 per cent., they are also readily formed at about the same temperature. By treatment with some sherry wines alone they are produced, though not very readily. A slight acidity of the reagent usually favours their production, as does the addition of 10 to 15 per cent, alcohol; though neither of these is absolutely essential, and the variety of reagents and mixtures which produce them is endless. According to the sp. gr. of the solution in which they are produced, the temperature, and other circumstances, their form and duration is modified. The temperature most favorable for their production, in the larger number of cases, is somewhat below 98° Fahr., and that in all the mammalia that I have examined alike; above that temperature they are quickly dissolved, and much below it,with most reagents, they are formed slowly and imperfectly, if at all. A solution of urea, as first stated by Kolliker, and others after him, will produce these appearances in the blood both of frogs and of mammals. This is most readily effected by drying a drop of the solution upon a slide, putting the blood upon this, and covering it. Salt solution, 0’6 per cent., as described in a recent paper, produces these appearances well in defibrinated frog’s blood on the warm stage. By this treatment, too, the nucleus of the red corpuscle is sometimes very clearly shown, and the reticular fibres which it contains, with the limiting membrane which encloses it, in places penetrated by the fibres, as recently described and figured by Dr. Klein3 in this Journal, and by Fleming,3 are very apparent.