ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTEES. 237 



older cells as having the strongest tendency to disintegration. It is prob- 

 able that the Blood-corpuscles, even whilst they are circulating in the living 

 vessels, are liable to alterations of form from variations in the density of the 

 fluid in which they float; and that such alterations may be constantly con- 

 nected with certain disordered states of the system. 1 Thus, even with- 

 out such an alteration in the Blood as w r ould constitute disease, its propor- 



Red and white corpuscles in blood from the finger X 2800 linear. The large, smooth, circular bodies 

 are the red corpuscles. Three very small red corpusck-s are less than l-80()0th of an inch in diameter. 

 The smallest particles are composed of matter like that of which the white blood-corpuscle (6) consists. 

 Threads of fibrin undergoing coagulation are observed between the corpuscles, a, red corpuscle, ex- 

 hibiting angular projections; below it and to the left is another with still more pointed processes. 



tion of water may be temporarily so much diminished by diuresis or exces- 

 sive perspiration, unbalanced by a corresponding ingestion of liquid, that 

 the corpuscles may be made to present a granulated edge; which is rendered 

 smooth again by the dilution of the liquor sanguinis with water. We hence 

 see the necessity, in examining the Blood microscopically, for employing a 

 fluid for its dilution, that shall be as nearly as possible of the same char- 

 acter with its ordinary "liquor sanguinis." In the following Fig. (103), 

 which shows the form and size of the red blood-corpuscles of animals be- 

 longing to each division of the Vetebrate class, most accurately drawn to 

 scale by Mr. Gulliver, 2 it will be seen that whilst in Man and all Mammalia, 

 with the exception of the Camel tribe (4), they are circular, and destitute of 

 a nucleus, or apyrenrematous, 3 in Birds, Reptiles, and Fish, except only 

 some of the lowest forms of the last, the corpuscles are uniformly oval and 

 nucleated, or pyrenrematous : in the Camel tribe, though the corpuscles are 

 oval, yet they conform to the Mammalian type in being free from a nucleus, 

 and in their small size. Mr. Gulliver has particularly insisted on this dif- 

 ference in the blood of the Mammalian and Oviparous Vertebrata, main- 

 taining it to be the only single, universal, and characteristic difference be- 

 tween them. 4 



1 See Dr. G. O. Eees's Gulstonian Lectures, in the Medical Gazette for 1845. 



2 See Proceedings of the Zoolog. Soc. of London, 18G2, p. 101. 



3 a. not, TTvpf/v, a nucleus, and aJ/za, blood. 



4 The following measurements of the blood of domestic animals (expressed in vul- 

 gar fractions of an English inch) have been selected from Mr. Gulliver's observa- 

 tions, as the most likely to become of interest in Juridical inquiries: 



Man, . 

 Dog, . 

 Hare, 

 Babbit, 

 Eat, . 



