47 



of shape from osmo!?is, irregular contractions or puckering, 

 and granulation ; but the regular form of the red corpuscle 

 in this class, including man, is a circular biconcave disc ; 

 excepting the camels, all of which have oval discs, but these 

 still in size and structure are quite mammalian. Some 

 orders of mammalia, as the Euminants, are characterized by 

 the smallness of their red corpuscles ; and other orders, as 

 the Edentates, by the comparative largeness of those discs. 



The size of the red corpuscles is not a question merely of 

 curiosity, by no means unimportant, as is too often supposed 

 or ignorantly asserted, but is connected with the rest of the 

 organization of the animal, especially with the perfection 

 of the lungs and their function, in direct relation to which 

 the largest proportion of surface is afforded by those 

 corpuscles in subordination to their office as carriers of 

 oxygen. This extension of their aggregate surface is 

 provided by their relative abundance and small size ; by 

 which minuteness the sum of the surface of a given 

 quantity of them is vastly increased, just as the surface 

 of an ounce of lead would be greater divided into small 

 shot than into bullets. Given, therefore, the proportionate 

 quantity of blood and of the amount and size of the red 

 corpuscles of different species, the comparative degrees of 

 heat in such species might, ceteris paribus, be inferred. Of 

 the numerous proofs, by the researches of John Davy, 

 Christison and others, that it is by the red corpuscles that 

 the oxygen is carried to vivify the system, the most remark- 

 able one is that of Brown— Sequard, almost like a miracle 

 of the middle ages. Into the blood vessels of a dead and 

 stark limb, on all parts of which the galvanic stimulus was quite 

 powerless, he injected red corpuscles charged with oxygen, 

 after which operation the muscles and fingers relaxed, so far 

 by an actual rcvivilication, and became obedient or sensible 

 to galvanism. 



As to structure, the Mammalian corpuscle consists mainly 

 of a matter soluble in water, and of a thin membranous 

 base which must by no means be confounded with a nu- 



