1823.] ah Examination of the Mlobit Wt 



investigation of the blood, are the albumen, the seruni, the ivhit^ 

 globule, and the colouring matter. White of ^gg is albumetl 

 nearly pure, but the serum of ox ot sheep's blood is purer, as the 

 white of egg always contains light membranous floccuh, Which 

 are not albumen. 



The coagulation of albumen by heat being so characteristic tt 

 property, and the cause of it difficult to discover, experiments 

 were made to determine the circumstances which accompany it. 

 By heating white of e.gg in tubes placed in water oter a lamp, the 

 following results were obtained : 



At 140° Fahr. the white of egg remained thin and clear. 



145® an opalescent tint appeared at the lower part of the 

 tube. 



149° the opalescent portion became solid, while the Upper 

 portion remained fluid. 



168° the opalescent appearance occurred in the upper part 

 of the tube. 



165° the solidification was complete. 

 The authors conclude that 158° is about the coagulating 

 point ; coagulated albumen, when examined by the microscope, 

 presents the same white globules which have been already men- 

 tioned. None of the circumstances which accompany the coa^ 

 gulation of albumen lead to a discovery of its cause. The 

 authors then refer merely to the opinions of Fourcroy and 

 Scheele as being erroneous. M. Thenard's opinion, that it is 

 derived merely from the cohesion of the molecules of the albu- 

 men, they consider it difficult ^o substantiate by experiment; 

 and they also think it possible, but not easily demonstrable, that 

 the caustic soda necessary to the solution of the albumeri may 

 become carbonate by the decomposition of a small portion ot 

 animal matter, and so become incapable of retaining the albu- 

 men in solution. The authors then remark, that the action 

 of voltaic electricity elucidates the state of combination which 

 exists between the albumen and the soda ; many other well- 

 known experiments, they observe, show that this substance is 

 also capable of combining with metallic oxides. When a metal- 

 lic salt is precipitated by albumen, a portion of the acid is 

 retained by the oxide, and all the oxide is not in combination 

 with the animal matter, for the soda of the albumen decomposes 

 a part of the salt, independently of it. When the decomposition 

 of albumen is effected by the pile, with a copper wdre, a com- 

 pound is obtained, which consists of water, albumen, and oxide 

 of copper : when moist, it is slightly green, and when dried, of 

 -a turquoise colour. If an iron wire be employed, then a com- 

 pound of albumen and oxide of iron is obtained. The coagula- 

 tion of albumen by alcohol is owing to the affinity of this fluid 

 for soda ; and it is stated to be the best mode of procuring albu- 

 men in a state of purity. When examined by reagents, it does 



