256 BLOOD 



On comparing the composition of the blood of the different 

 vertebrala, we find in the first place, that amongst mammalia the 

 omnivora exhibit the greatest number of corpuscles, and hence, 

 also, the largest quantity of iron and of soluble phosphates. 

 Fibrin also occurs in larger quantities here than in the blood of 

 animals of other dietetic habits. The solid constituents of the serum 

 also preponderate in the blood of these animals. The serum of the 

 omnivora contains less salts than that of many other mammalia. 



The blood of the carnivora generally contains nearly as many 

 blood-cells as that of the omnivora : there is less fibrin but more 

 fat in the blood of these animals than in that of the herbivora. 

 The quantitative relations of the constituents of the blood vary con- 

 siderably in the different species belonging to this class. A similar 

 remark may be made regarding the blood of the herbivora, which 

 on an average contains fewer blood- corpuscles than that of the car- 

 nivora, but the deviations from this rule are as great in the different 

 species of this class as in the carnivora. We may, however, hope 

 that a more careful study of the composition of the blood of 

 these three groups of animals will enable us to detect more definite 

 differences between them. 



The blood of birds is rich in corpuscles, and stands next in 

 this respect to that of the pig; it contains, however, more nbrin 

 and fat, and less albumen, than that of the mammalia. 



In the cold-blooded vertebrate the blood is poorer in corpuscles 

 and richer in water than in the other vertebrata. 



Although the mollusca possess a vascular system, consisting of 

 arteries and veins and an aortic heart, their blood differs very con- 

 siderably from that of the classes of animals immediately above 

 them ; being a white or bluish juice. C. Schmidt * found the 

 blood of the pond-mussel (anodonta cygnea) colourless and slightly 

 alkaline; it deposited a pale fibrinous coagulum, which on evapora- 

 tion exhibited beautiful crystals resembling Gaylussite, and con- 

 sisting of carbonate of lime and some carbonate of soda. The 

 albumen was mostly combined with lime. This blood contained 

 only 0'854f of solid constituents, and of these there were 0*033 of 

 a fibrin-like substance, 0-565 of albumen, 0-189 of lime, 0-033 of 

 phosphate of soda, chloride of sodium and sulphate of lime, and 

 0*034 of phosphate of lime. 



E. Harless and v. Bibraf investigated the blood of the large 



* Zu vergleichenden Physiol. Milan, 1846, S. 5860 [or Taylor's Scientific 

 Memoirs, vol. 5, p. 26.] 



t Muller's Arch. 1847. S. 148157. 



