EXHALATION OF ORGANIC MATTER. 449 



In a number of observations made on his own person, the 

 following variations were noted : 1 



On rising in the morning, after a sound night's rest, the 

 breath contained no ammonia. 



In the evening, when fatigued and exhausted, and after 

 exercise, the exhalation was generally considerable. 



During a high temperature the exhalation is considerable, 

 especially after exercise; but during cold weather the exha- 

 lation is very slight, or it may be absent altogether. 



The amount of ammonia exhaled is greatest at the end 

 of an expiration. If short and rapid expirations be made, 

 the exhalation ceases until the respirations become deeper 

 and more prolonged. 



Ammonia has long been recognized as an exhalation from 

 the human body in health, from the skin as well as the lungs. 

 Dr. Richardson calls attention in his essay to the observa- 

 tions of Mr. Reade, Dr. Reuling, Viale and Latini, and 

 others on this subject. Reuling has shown that the quantity 

 of ammonia in the expired air is increased in certain diseases, 

 particularly in uremia. 2 Its characters in the expired air 

 are frequently so marked, that patients who are entirely 

 unacquainted with the pathology of uremia sometimes 

 recognize an ammoniacal odor in their own breath. 



Exhalation of Organic Matter, etc. The pulmonary sur- 

 face exhales a small quantity of organic matter. This has 

 never been collected in sufficient quantity to enable us to 

 recognize in it any peculiar or distinctive properties, but its 

 presence may be demonstrated by the fact that a sponge 

 completely saturated with the exhalations from the lungs, or 

 the vapor from the lungs condensed in a glass vessel, will 

 undergo putrefaction, a property distinctive of organic sub- 

 stances. 



It is well known that certain substances which are only 



1 The Came of the Coagulation of the Blood, London, 1857, p. 360 ct seq. 



2 InLEHMAXN's Physiological Chemistry, Philadelphia, 1855, vol. ii n p. 434. 



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