593 



To the facts and arguments adduced in the preceding quotation^ 

 two other observations may now be added, which are both conclusive 

 as to the vesicular structure of the erythrocyte. One is that the en- 

 velope can be stained distinctively, the other that the edge of the 

 corpuscle can be indented so as almost to come in contact with the 

 opposite edge, a phenomenon which is quite incompatible with the con- 

 ception of a homogeneous or porous stroma. 



The staining of the membrane can be effected by adding to a 

 fresh preparation of blood a 1% solution of Spiller's purple^). The 

 haemoglobin is discharged and the empty corpuscle appears encircled 

 by a stained and sharply defined, limiting membrane. A similar effect 

 is obtainable with methylene blue, but less easily. The envelope is 

 also stained, of a faint slaty hue suggestive of myelin, by osmic acid. 

 These reactions will be again alluded to in discussing the nature of 

 the membrane. 



The indenting of the corpuscles can be seen in blood containing 

 trypanosomes, such as occur in tetze-fly disease. These organisms 

 are impelled with considerable force, often enough to displace the 

 corpuscles, by the activity of their flagella. But occasionally there i& 

 a direct impact of the tapered head of the trypanosome against the 

 edge of an erythrocyte which happens by some means to be fixed and 

 cannot therefore be bodily displaced by the organism. Under these 

 circumstances the edge of thie corpuscle is dimpled in ; sometimes 

 deeply, so that the head of the trypanosome is pressed into a sort of 

 cup. When the organism moves away the cupping immediately dis- 

 appears and the elasticity of the envelope causes the corpuscle to re- 

 sume its normal shape. I know of no observation which is more con- 

 vincing of the vesicular nature of the erythrocyte than this one. 



2. On the nature of the membrane. The chemical nature 

 of the "stroma" (envelope) of the erythrocyte has been studied by 

 various observers and is well known. It consists, besides water, mainly 

 of Proteids combined with nuclein (nucleo-proteids) and it contains also 

 lecithin and Cholesterin. These are all constituents of cell-protoplasm, 

 and it is probable therefore that the envelope of the vesicle is a thin 

 remainder of the protoplasm of the original erythroblast. The pro- 

 portion of lecithin and Cholesterin to nucleoproteid and proteids is not 

 larger than in ordinary protoplasm. Thus in two analyses of the 

 "stroma" of human blood- corpuscles by Hoppe-Seyler and Jüdell^) 



1) Essentials of Histology, 6. Edit., 1902, p. 22. Spiller's purple 

 seems to be a form of methyl-violet. 



2) Hoppe-Seyler's Med.-chem. Unters., 1866. 



Annt. km. XXVI. Aufsätze. 38 



