BLOOD-GLOBULES. 219 



mechanically deposited in the globuline, but the two substances are 

 intimately mingled throughout the mass of the blood-globule, just 

 as the fibrin and albumen are mingled in the plasma. Haematine 

 contains, like the other coloring matters, a small proportion of iron. 

 This iron has been supposed to exist under the form of an oxide; 

 and to contribute directly in this way to the red color of the sub- 

 stance in question. But it is now ascertained that although the 

 iron is found in an oxidized form in the ashes of the blood-globules 

 after they have been destroyed by heat, its oxidation probably takes 

 place during the process of incineration. So far as we know, there- 

 fore, the iron exists originally in the haematine as an ultimate 

 element, directly combined with the other ingredients of this sub- 

 stance, in the same manner as the carbon, the hydrogen, or the 



nitrogen. 



The blood-globules of all the warm-blooded quadrupeds, with 

 the exception of the family of the camelidae, resemble those of the 

 human species in shape and structure. They differ, however, some- 

 what in size, being usually rather smaller than in man. There are 

 but two species in which they are known to be larger than in man, 

 viz., the Indian elephant, in which they are ?>?$$ ^ an i ncn an d 

 the two-toed sloth (Bradypus didactylus), in which they are 3B V^ of 

 an inch in diameter. In the musk deer of Java they are smaller 

 than in any other known species, measuring rather less than T2 Jnir 

 of an inch. The following is a list showing the size of the red 

 globules of the blood in the principal mammalian species, taken 

 from the measurement of Mr. Gulliver. 1 



DIAMETER OF RED GLOBULES IN THE 



Ape . . . j^gof an inch. Cat . . . ? J ff5 of an inch. 



Horse . . . > " Fox ... ^ 



Ox - . . ifa Wolf . . . ^ 



Sheep. . . ^j " Elephant . . 



Goat . . . W J SV " Red deer . . 



Dog ... ^ " Musk deer. . 



In all these instances the form and general appearance of the 

 globules are the same. The only exception to this rule among the 

 mammalians is in the family of the camelidae (camel, dromedary, 

 lama), in which the globules present an oval outline instead of a 

 circular one. In other respects they resemble the foregoing. 



In the three remaining classes of vertebrate animals, viz., birds, 



1 In Works of William Hevrson, Syrtenham edition, London, 1846, p. 327. 



