of the Bed Blood Corpuscle. 19 



in it to cover the surface of a sphere having the exact diameter of 

 the red corpuscles when rendered globular by the action of water. 



In one of my experiments on the action of water upon blood, as 

 detailed in that paper, the development of Bacteria so obscured 

 these supposed membranous cell walls that they became unrecog- 

 nizable after standing seventy-two hours, so that, in order to deter- 

 mine whether their apparent insolubility could be overcome by 

 prolonged maceration, I made the following additional investiga- 

 tions : — 



On the 24th of March, 1870, I thoroughly stirred two fluid- 

 drachms of blood into two fluid-ounces of fresh water, and allowed 

 the mixture to stand undisturbed for forty-eight hours, when a 

 light and flocculent deposit of a pale pink colour, occupying about 

 half a fluid-ounce of the liquid, had fallen to the bottom of the 

 vessel. On examination under the gij-inch objective, this was 

 found to be 'chiefly composed of very transparent spherical bodies, 

 about T^Wth of an inch in diameter, which became beautifully dis- 

 tinct and quite visible with an ordinary :^-inch when tinted by a 

 minute portion of aniline solution introduced at the margin of the 

 cover. In order to prevent the development of Bacteria, about two 

 fluid-drachms of carbolic acid solution were added, and the mixture 

 kept covered in a room of ordinary temperature for four weeks, at 

 the end of which time the delicate colourless spheres were still dis- 

 tinctly visible, although they had a little further diminished in size, 

 only measuring about 5 oWth of an inch across. 



From these various observations, it appears that human red 

 blood corpuscles are composed of two difierent ingredients, the one 

 h£emato-crystallin, of a crimson colour, and dissolving freely in 

 water, the other of a whitish hue, and insoluble in water, even on 

 prolonged maceration ; but so minute are the blood disks in mam- 

 malia generally, that it is extremely difiicult to determine the exact 

 relation of these constituents to each other. It occurred to me, 

 however, that investigations upon the large blood globules of rep- 

 tiles might be more successful, and after numerous disappointments 

 I procured, in November last, from a former patient near my late 

 residence on Cayuga Lake, in Western New York, two specimens 

 of the Menobranchus or Proteus, whose red blood disks, as far as 

 known, with a single exception, exceed those of all other animals in 

 magnitude, measuring about T^uth of an inch in length by e^oth 

 of an inch in breadth, and actually visible, in a strong light, 

 to the naked eye of a myopic person like myself. The gigantic 

 corpuscles being about six times the diameter, and consequently 

 216 times the magnitude of those of man, evidently afibrd much 

 better opportunities for the detection of their membranous parietes, 

 if such exist ; and in addition to this great advantage, I discovered, 

 quite unexpectedly, in the course of my experiments upon them, 



