BLOOD. 1 13 



that corpuscles, instead of coiisistiug of fibrin, are mainly 

 composed of fatty matter (either cholesterin or some allied 

 substance), combined with albumen, as occurs in the yelk 

 of eggs. In this view I cannot coincide, although I fully 

 believe that albumen and fat do take a very active part in 

 the formation of all the animal tissues, and, consequently, 

 in the production of the blood- corpuscles. In this instance, 

 the formative process has advanced so far that we can expect 

 to find the original materials of formation present in only very 

 small quantities. It is true that the fibrin and the blood- 

 corpuscles contain a greater relative proportion of fat than the 

 other constituents of the blood ; yet even in fibrin the propor- 

 tion amounts to only 5|^, and the fat cannot therefore be re- 

 garded as a preponderating constituent of this substance. That 

 the fat is not actually cholesterin seems pretty clear from the 

 fact of the ready solubility of the corpuscles in caustic potash. 



The diameter of the nucleus is usually about one-fourth or 

 one-fifth of the diameter of the blood-corpuscle. In the 

 amphibia it varies from "002 to '005 ; in fishes, from 'OOIG to 

 •0025 ; in birds, its length is about '002, and in the mammalia 

 •0008 of a line. 



I have made the following observations with regard to the 

 nuclei in the blood of man,^ the carp, and the frog. The 

 nuclei in the frog appear, after the solution of the capsule and 

 hsemato-globulin, as partly elliptical and partly cyhndrical. 

 After washing them for a day or two in order to remove the 

 colouring matter and albumen, they assume a more spherical 

 form, and most of them present a granulated appearance on 

 the surface. I cannot, however, positively assert that granular 

 cells were present, nor did I observe the nuclei separate into 

 distinct portions during this treatment. The nuclei, even 

 when moist, were not soluble in boiling ether. When dried, 

 moistened with water, and then observed under the micro- 

 scope, several nuclei were seen floating about, apparently un- 

 altered; many were, however, connected together in such a 

 manner as to prevent their whole outline from being apparent. 

 Upon treating the dry nuclei with ether, appearances similar 



' I allude to the nearly colourless sediment which may be obtained by washing 

 blood with a large quantity of water, and which is found to contain lymph-corpuscles 

 and fragments of capsules. 



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