354 LIQUID PARTS OF ANIMALS. 



In the year 1831, M. Lecami published a most elaborate me- 

 moir on the blood. * His chemical analysis of that fluid was 

 more minute than that of Berzelius, and he detected several con- 

 stituents which had escaped the sagacity of that chemist. He 

 then made a comparative analysis of the blood of individuals of 

 different ages, sexes, and temperaments ; and he terminated his 

 researches by an analysis of the blood of an individual labouring 

 under jaundice, in order to determine whether the matter of bile 

 was present in it or not. In 1837, M. Lecanu, when he received 

 the degree of M. D. published a thesis, entitled Etudes Chimiques 

 sur le Sang Humain. In this thesis he gives a detailed account of 

 all that has been done respecting the chemical analysis of the 

 blood either by himself, or the many chemical writers who preceded 

 him. To this thesis I refer such readers as are interested in 

 such historical details ; and therefore terminate this historical in- 

 troduction here without mentioning the names of many other in- 

 dividuals to whom we owe important facts respecting the blood. 

 Many of these will be noticed in the course of the statements 

 which will occupy this chapter. 



After this historical sketch of the progress of the chemical in- 

 vestigation of the blood, I proceed to lay the principal facts which 

 have been ascertained before the reader. 



1. Blood is a liquid which circulates through living animals, 

 and which is destined to nourish the different parts of the animal 

 body, and to supply the part of the waste which is constantly 

 going on in it. In mammalia, birds, reptiles, fishes, and anne- 

 lides, it has a red colour ; while in the Crustacea, arachnides, in- 

 sects, and zoophytes, it is white or colourless. Hitherto chemists 

 have confined their examination to human blood and to the blood 

 of certain mammalia, especially of the ox and sheep ; the white 

 or colourless blood still remains unexamined. 



When blood is drawn from a vein its colour is dark, when from 

 an artery it is scarlet. And venous blood, upon exposure to. the 

 air, speedily assumes a scarlet colour. Fresh-drawn blood has 

 a peculiar odour, which has been compared to that of garlic, 

 though scarcely, I think, with propriety. It has an unctuous 

 feel and a certain viscidity, which gradually increases as the tem- 

 perature sinks. 



Its mean specific gravity is 1*0507. This will appear from 

 the following little table : 



* Jour, de Pharmacie, xvii. 485 and 545. 

 3 



