ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 245 



and Globulin are also products of the decomposition of the albuminous con- 

 stituent of Haemoglobin. 



The coloring matter of the blood, or haemoglobin, enters largely into the 

 composition of the corpuscles. It is capable of assuming the crystalline form, 



FIG. 111. 



FIG. 112. 



FIG. 113. 



Fin. 111. Spontaneous changes in form of Red corpuscles of Guinea-pig's Blood, within an hour after 

 removal from the body. 



Fie;. 112. Perfect Tetrahedral Crystals formed from Guinea-pig's Blood. In many eases, one Corpuscle 

 became one Crystal. 



the crystals being obtained with the greatest facility from the blood of the 

 dog, horse, guinea-pig, and goose, less easily from the blood of man, and with 

 the greatest difficulty from the mouse, the mole, and the bat. 1 In some in- 

 stances it is only requisite to dilute 

 the blood and allow one or two drops 

 to dry spontaneously. In others, an 

 abundant crop may be obtained by 

 transmitting air free from carbonic 

 acid through the blood for several 

 hours ; or the blood after being defib- 

 riuatecl maybe frozen (Rollett's plan) 

 and allowed slowly to thaw ; or (Bott- 

 cher's method) a considerable quantity 

 of cold water may be injected into the 

 veins of the animal whilst it is being 

 killed by chloroform inhalation, the 

 blood removed from the heart mixed 

 with its own volume of cold water and 

 some alcohol added, when the whole 

 mass changes into a crystalline pap ; 



or (Kiihue's and Thiry's plan) the blood left after the formation of a clot is 

 mingled with some 0.5 per cent, aqueous solution of crystallized ox-bile 

 (tauro- and glycocholate of soda), and then with alcohol (90 per cent.) con- 

 taining a little acetic acid. The method given by Preyer as the best adapted 

 for microscopical investigation is that to a small quantity of blood free from 

 fibrin, sufficient water should be added to give a clear solution ; if on evap- 

 oration in the cold a drop of the solution covered by a thin slip of glass give 

 no crystals, about a quarter of its volume of alcohol must be added and the 

 fluid placed in a freezing mixture: crystals will in almost all instances be 

 immediately formed. Speaking generally, in order to obtain good crystals, 

 the corpuscles must be dissolved, and the coloring matter thrown down by 



1 Hoppe-Seyler, Med.-Chem. Untersuch., 1867, p. 174. 



Blood-Crystals, (1) prismatic, from Human 

 blood, (2) tetrahedral, from Pig's blood, (3) hex- 

 agonal plates, from Squirrel's blood. 



