THE BLOOD. 



145 



The blood, according to M. Le Canu, consists of the following 

 constituents : 



When blood, venous or arterial, is immediately placed in the 

 vacuum of an air pumps, or coagulates in the air h , or is received 

 from a vein into pure hydrogen 1 , it emits a large quantity of car- 

 bonic acid gas. Professor Brande obtained two cubic inches from 

 every ounce of blood; Sir C.Scudamore, less than half a cubic inch 

 from six ounces. k The quantity is said to be much greater after 

 a meal, and much less if the blood is buffy. 



6 Vogel, Annales de Chimie, t. xciii. 



h Professor Brande, Phil- Trans. 1818. p. 181. 



* Dr. Stevens, London Medical Gazette, 1834, No. xxviii. Mr. Hoffman, 

 id. 1833, No. xxvi. 



k Phil. Trans. 1820. p. 6. 1. c. p. 107. 



Blumenbach, found, in 1812, that a small portion of the purest air, infused 

 into the jugular vein, excited palpitations, drowsiness, convulsions ; and, if the 

 quantity was a little increased, even death ensued. (Medicin. Biblioth. vol. i. 

 p. 177.) Bichat observed the same effects in his experiments. (Journal de 

 Saute, $c. de Bordeaux, t. ii. p. 61.) But Dr. Magendie stated, in 1809, to the 

 Institute, that this assertion is incorrect. If air is injected rapidly, the animal 

 screams and dies in a moment : but if slowly, he informs us that no inconve- 

 nience results, and that some animals bear the injection of enormous quantities 

 without perishing. (Precis Elementaire de Physiologic. 2d edition, 1825. t. ii. 

 p. 433. sqq.) Dr. Blundel injected five drams into the femoral vein of a very 



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