REPORT ON ANIMAL PHYSIOLOGY, 117 



The corpuscles consist of a nucleus inclosed in a membrane of 

 coloured matter, which membrane bursts, and the nuclei thus al- 

 lowed to escape attract each other and form the solid coagulum, 

 which is coloured by the broken membranes, and from which 

 the colouring matter may be washed out by water. This opinion, 

 which appeared to be confirmed by the observations of Prevost 

 and Dumas, of Dutrochet, and of H. M. Edwards, has been 

 very generally received. But it is certainly unfounded. For 

 the fibrin may be separated from the blood by stirring, whilst 

 the corpuscles remain in the serum unbroken and unchanged : 

 the serum, far from effecting their solution, supplies the best 

 medium in which they may be preserved for observation: if 

 in human blood the coagulation be retarded by adding a few 

 drops of solution of subcarb. potass., the corpuscles descend, 

 from their superior weight, before coagulation takes place : in 

 the course of half an hour a tender coagulum is formed, of which 

 the lower part (as far as the corpuscles reach) is red, the upper 

 pale and thready : operating on the blood of the frog, Miiller 

 has succeeded in separating, by the filter*, the large corpuscles 

 of that animal from the clear liquor, which last afterwards sepa- 

 rates into fibrin and serum : fibrin is not soluble in water, the 

 corpuscles are so in part ; and, in general, the two present some- 

 what different chemical reagencies. 



The Corpuscles. — These bodies, called collectively cruor, 

 have been objects of much interest ever since they were first 

 observed by Malpighi. All that relates to them is even yet 

 matter of controversy, — their form, their size, their composition, 

 the cause of their colour. They have been too frequently ob- 

 served in water, rather than in serum, by wliich the two first 

 qualities are speedily altered. 



Form. — They exist in all vertebral animals as round or oval 

 bodies, with well-defined edges. They are semi-transpai'ent 

 and pale Avhen seen singly ; but present the colour of the 

 blood when seen by reflected light or in masses. 

 In all the Mammalia they are circular. 



In the other Vertebrata they are oblong. De Blainville has 

 observed both these forms in Fishes, and Miiller in the 

 Frog, who thinks that the round corpuscles, one sixth of 

 the size of the others, belong to the lymph or the chyle. 

 In all the Vertebrata they are flat. Rudolphi states, that they 

 are flattest in the x\mphibia, less so in Birds, least of all in 

 Man. 

 Hodgkin and Lister find the proportion of axes in Man to 

 be 1: 4-5. 



* Miiller, p. 106. The filter was composed of delicate animal membrane, 

 moistened bladder, and covered a glass tube from which the air was exhausted. 



