STRUCTURAL RELATIONS OF RED BLOOD-CORPUSCLES. 387 



matter cannot be extracted by corrosive sublimate from red 

 blood-corpuscles which have been preserved in alcohol. It was, 

 therefore, of great service to me that, by a lucky chance and by 

 the kindness of Professor A. Rosenberg, I was soon again 

 possessed of fresh camel's blood, when the animal which I had 

 already used once was purchased by the Dorpat Veterinary 

 Institution. 



The blood of this animal, after being defibrinated, was treated 

 in the manner above described. My statements witb regard to 

 the camel's blood were then confirmed in every respect. Of the 

 blood-co7'p2iscles decolorised hi/ the alcoholic soltttion of corrosive 

 sublimate, at least one ha f show two comjwnent parts — a homo- 

 geneous cortical layer and a granular mass situate in the interior, 

 which stains more deeply with carmine (fig, 8, a, b). This is 

 the granular protoplasm, which is accumulated round the nucleus. 

 Processes of the protoplasm, presenting the varied appearances 

 observed in the blood-corpuscles of man, I have not found in 

 those of the camel. This may be due to accidental circum- 

 stances, which cannot at present be determined. The important 

 fact, however, in the structure of the mammalian blood-cor- 

 puscle is here to be recorded, that within the homogeneous 

 cortical layer a second constituent part can be demonstrated, 

 which hitherto no one has seen. In the interior of this, just as 

 in the protoplasm of the red blood-corpuscles of man, is situated 

 a nucleus. Any one unaccustomed to examining red blood- 

 corpuscles would be inclined to consider the central body, repre- 

 sented in fig. 8, a and b, as the nucleus. But a closer 

 acquaintance with the object teaches that two things must here 

 be distinguished. The nucleus possesses, as I have already 

 proved, a membrane with a double contour, is less granular, and 

 encloses usually a nucleolus. Neither does it become coloured 

 by carmine, like the protoplasm. When surrounded by the 

 latter it is not always seen, but in other more favorable cases 

 the sharply defined ellipse is perceived within the granular mass 

 (fig. 8, c). This nucleus then appears to agree accurately both 

 in form and size with the nuclei, which i have isolated by 

 different methods from the blood-corpuscles of the camel. 



What I was therefore obliged to take for granted as the cause 

 of the non-visibility of the protoplasm and nucleus has proved to 

 be quite correct. The homogeneous cortical layer of the camel's 

 blood-corpuscles is comparatively thick, and at the same time 

 very highly refractive. Observation is thereby impeded. And 

 if the blood-corpuscles, which have become rigid in concentrated 

 alcohol are decolorised by acetic acid, the advantage gained by 

 the decoloration is again lost by the swelling which takes place. 

 The blood-corpuscles then indeed appear colourless, but are 



VOL. XVII. NEW SEE. C C 



