380 POISONS, CONTAGIONS, MIASMS. 



nature or quantity. The food taken is not employed in increas- 

 ing the size of the body, but merely for the purpose of replacing 

 any substances which may be consumed by the various actions 

 in the organism ; every motion, every manifestation of organic 

 properties, and every organic action being attended by a change 

 in the material of the body, and by the assumption of a new form 

 by its constituents.* 



But in a child this normal condition of sustenance is accom- 

 panied by an abnormal condition of growth, and increase in the 

 size of the body, and of each individual part of it. Hence, 

 there must be a much larger quantity of foreign substances, not 

 belonging to the organism, diffused through every part of the 

 blood in the body of a young individual. 



When the organs of secretion are in proper action, these 

 substances will be removed from the system ; but when the 

 functions of those organs are impeded, they will remain in 

 the blood, or become accumulated in particular parts of the 

 body. The skin, lungs, and other organs, assume the functions 

 of the diseased secreting organs, and the accumulated substances 

 are eliminated by them. If, when thus exhaled, these sub- 

 stances happen to be in the state of progressive transformation, 

 they are contagious ; that is, they are able to produce the 

 same state of disease in another healthy organism, provided the 

 latter organism is susceptible of their action — or, in other words, 

 contains a matter capable of suffering the same process of 

 decomposition. 



The production of matters of this kind, which render the body 

 susceptible of contagion, may be occasioned by the manner of 

 living, or by the nutriment taken by an individual. A super- 

 abundance of strong and otherwise wholesome food may produce 

 them, as well as a deficiency of nutriment, uncleanliness, or 

 even the use of decayed substances as food. 



* The experiments of Barruel upon the different odors emitted from 

 blood on the addition of sulphuric acid, prove that peculiar substances are 

 contained in the blood of different individuals ; the blood of a man of a fair 

 complexion and that of a man of dark complexion were found to yield dif- 

 ferent odors ; the blood of animals also differed in this respect very per- 

 ceptibly from that of man. 



