284 ANNUAL OF SCIENTIFIC DISCOVERY. 



ardson has proved that in the experiment of passing the vapor of blood 

 through blood, coagulation is suspended by the agency of a volatile princi- 

 ple; and he has also proved by experiment that this volatile principle is 

 ammonia. Now, the vapor of blood is a large constituent of the vapor of 

 breath, and the effect of passing this latter vapor through blood is precisely 

 similar to that of the former. If a portion of blood be received in a vessel, 

 and the expired air and vapor of breath, collected in quantity and in a suit- 

 able apparatus, be passed through it, the fluidity of the blood is maintained 

 so long as the experiment is continued; thus furnishing a proof of the 

 escape of a volatile agent in the breath, which agent, by direct experiment 

 upon it, is proved to be ammonia. This experiment is, in all respects, most 

 satisfactory. Had it failed, the whole subject would again be enveloped in 

 its ancient mystery, and we should say with Brande, that the cause of coag- 

 ulation is still unexplained. True, we should know that the vapor of blood 

 sustains fluidity, and that its volatile alkali, ammonia, sustains fluidity also; 

 but so do the fixed alkalies, potash and soda, which are proved to be inopera- 

 tive as the cause of coagulation. If, then, the vapor of breath, which is 

 characterized by the same volatile agent as the vapor of blood, failed to pre- 

 vent coagulation, we must unavoidably be led to the conclusion, that, not- 

 withstanding the evidence of experiment in a given direction in favor of 

 ammonia, there is a still more subtle agency at work, even during the evolu- 

 tion of this alkali from newly-drawn blood, which is the true and ultimate 

 cause of coagulation. Ammonia, like potash and soda, would then be 

 looked upon as a mere proximate agent in sustaining fluidity, and its evo- 

 lution would cease to be acknowledged as the final and efficient cause of 

 coagulation. 



ON THE FORMATION OF UREA BY THE OXIDATION OF ALBUMIN- 

 OUS MATTERS. 



Bechamp has succeeded in showing that urea is one of the products of the 

 oxidation of albuminous bodies. The author effects the decomposition by 

 an alkaline solution of hypermanganate of potash. The fibrine of the blood 

 and gluten yield also urea by the same process. From these experiments it 

 is clear that the oxidation of albuminous matters under an alkaline influence 

 yields products very different from those obtained at a higher temperature 

 by means of oxidizing mixtures of peroxide of manganese or bichromate of 

 potash and sulphuric acid. Ann. de Chimie et de Physique, xlvii, 348. 



ON THE PRESENCE OF COPPER IN THE TISSUES OF PLANTS AND 



ANIMALS. 



Drs. Odling and Dupre, in a communication to the British Association, 

 stated that they had made more than one hundred examinations, by a great 

 variety of processes, and had recognized the presence of copper in nearly 

 every instance. In several specimens of wheat grain and human viscera the 

 copper had been estimated. From 100 grains of wheat-ash the authors had 

 obtained 251 thousandths of a grain, and from a sheep's liver rather more 

 than one-half a grain of oxide of copper. The process was to precipitate 

 the copper electroiytically on a platinum wire, to dissolve in nitric acid, and 

 to ignite the residue of the evaporated solution. 



