292 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



and the presence of hydrochloric acid was clearly demon- 

 strated. Hydrobromic acid, however, was not found. The 

 blood of sea -polyps gives no absorption band under the 

 spectroscope. It becomes slightly blue when traversed by a 

 current of carbonic-acid eras. The blood of the crab exhibits 

 similar characteristics ; and both contain a coagulable sub- 

 stance which cold nitric acid turns yellow. 21 A, November, 

 1873,1150. ' 



COAGULABILITY OF SERUM AND ALBUMEN DEPENDENT ON 

 THE PRESENCE OF CARBONIC ACID. 



A very suggestive and important paper has lately been 

 presented to the Academy of Sciences of Paris by Messrs. 

 Mathieu and Urbain, in which they show that if the gases 

 dissolved in the serum of blood be completely removed, an 

 albuminous liquid is obtained which does not coagulate even 

 at a temperature of 212. The same fact was also ascertain- 

 ed in regard to the albumen of the egg, and by the use of 

 proper pneumatic apparatus it became possible to extract 

 from this albumen, not only the gas, but also the volatile salts 

 which it contained ; and it was furthermore determined that, 

 Avhile the removal of the o-as renders the albumen uncoa;u- 

 lable by heat, the disappearance of the volatile salt converted 

 it into a substance analogous to o-lobuline. 



Other experiments showed that the greater part of the gas 

 in the albumen consists of carbonic acid, and that it is really 

 the presence of this which imparts the property of coagu- 

 lability. The other ingredients are nitrogen and oxygen in 

 very small percentage. The amount of carbonic -acid gas 

 varied from sixty-five to eighty-four per cent.; of oxygen 

 there was about two per cent., and of nitrogen from three to 

 five per cent. 



When the normal amount of oxygen and nitrogen was re- 

 stored to the albumen, no change took place in its properties, 

 but the introduction of a sufficient quantity of carbonic acid 

 was found to impart the power of coagulability under the 

 influence of heat. This property of removing the coagulabil- 

 ity of albumen by the extraction of carbonic acid, and re- 

 storing it on its return, will doubtless be applied with very 

 great effect to many manufactures in which albumen enters 

 largely. 



