SNAKE POISONS. 117 
fatty substances, some of which contain sulphur and phos- 
phorus, a great number of salts, such as the chlorides of 
potassium and sodium, chloro-hydrate of ammonia, the sul- 
phates of soda and potassa, the phosphates of soda, lime, and 
magnesia, the carbonates of soda, lime, and magnesia, and of 
alkaline salts, formed by fatty acids and lactic acid, has been 
detected in blood. This plasma contains also several gases 
in solution: oxygen, carbonic acid, and nitrogen, which are 
derived from the action of the air in the lungs. It has a 
peculiar mawkish taste, characteristic in some animals, and 
always exerts a well-marked alkaline reaction, which appears 
to be an essential part of its nature, for animal life ceases 
when, by direct injections, the blood can be made acid. 
In a healthy man 100 parts of blood contain on an average 
79 parts of water, 1 part of mineral salts, and 19 of albumi- 
nous substances, known by the name of hematosin, which 
proportions vary greatly with the state of health. In the 
blood of birds the relative quantity of water is generally some- 
what smaller than in a man, while it is greater in that of the 
batrachian reptiles and fishes. As much as 98 per cent. of 
water has been found in the blood of a frog. 
Besides the red globules, other colorless globules are seen, 
the number of which vary under different physiological con- 
ditions ; these are more apparent in the serwm when by coagu- 
lation the blood has separated itself into the former, a yellow- 
ish and transparent mass, and into a gelatinous mass of a deep 
red color, called clot, coagulwn or crassamentum. The phenom- 
enon of coagulation is produced by the fibrin, which remains 
in solution so long as the blood is under the influence of the 
vital principle; but separates from it when it is removed from 
the animal economy, carrying with it the blood-globules, in 
the same way that soluble albumen, used for the clarification 
