394 
PHYSIOLOGY OF THE BLOOD. 
The chemical constituents of the serum in 1000 parts, as given 
by Berzelius, are, 
Water 906 
Albumen - 080 
Chloride of potassium and sodium ------ 006 
Lactate of soda united to an animal matter - 004 
Carbonate and phosphate of soda, with animal matter - - 004 
1000 
On minute examination the cruor or crassamentum is found 
to consist of two parts, very easily separated by immersion, or 
washing in water. The more solid becomes whitish, and appears 
fibrous ; it is designated fibrine. The colouring matter is more or 
less dissolved in the water, and is denominated hoematozine, which 
Berzelius, by burning it in the open air, found to consist of oxide 
of iron, a mixture of carbonate and phosphate of lime, phosphate 
of magnesia, and subphosphate of oxide of iron, but was unable to 
detect iron by the liquid tests. Others have established these 
facts, and have also succeeded in testing iron by the liquid 
reagents. On transmitting a current of chlorine gas through a 
solution of red globules, the colour entirely disappeared ; white 
flocks were precipitated, and a transparent solution remained in 
which peroxide of iron was discovered. The real state in which 
it exists in the blood is unknown. 
Fibrine is found in the blood in two states ; as the central nu- 
cleus of the red globule and in solution it constitutes serum : 
muscular fibre is principally formed of it, and probably most of 
the fibrous membranes ; so that it may be said to constitute the 
greatest part of the soft solids of animals. 
The serum being solidified by exposure to a heat of 160° 
Fahr., a small quantity of a colourless limpid fluid may be 
pressed from it, which is termed serosity ; this contains about 
half its weight of animal matter combined with chloride of 
sodium. Of the animal matter a portion is albumen, which 
may be coagulated by galvanism. Serosity is supposed to pre- 
vent friction in the serous cavities, being secreted by the minute 
capillaries in the form of vapour, and again absorbed. 
The blood is subject to disease, and is also the medium by 
which many diseases are conveyed to their respective organs. 
The first morbid change we shall notice relates to its quantity, 
which may be excessive or deficient. The former is denominated 
plethora, and is generally caused by too much nutritious food 
with too little exercise : the latter is termed ansemia, which is 
occasioned by a morbid state of the organs, or functions, that 
concur to effect the formation of blood. A common cause 
of anemia is dyspepsia; a more immediate cause is the loss of 
