274 NATURE AND LIFE. 



After examining the alterations produced in the living, 

 we have to consider those occasioned by fermentations in 

 the dead. When life has retreated by slow degrees from all 

 the parts of an organized being ; when, after all partial 

 deaths have occurred, total death has possessed the depths 

 of the subject, and broken all the springs of its activity, the 

 work of putrefaction begins. Its task is to unmake this 

 body, to destroy its forms, and dissever its materials. The 

 work to be done is to disorganize it, to reduce it into 

 solids, liquids, and gases, fit to go back again into the vast 

 reservoir whence new life is incessantly issuing. This is 

 the task that heat, moisture, air, and germs, will undertake 

 in unison. It is all performed with steady diligence. Na- 

 ture knows no delays ; as soon as the body is cold, the pro- 

 tecting coating that covers all its surface, the epithelium, 

 decays in places, particularly in the moister parts. The 

 agents of disorganization, vibrios and bacteria, or rather 

 the germs of these thread-like corpuscles, penetrate through 

 the skin, wind into the small ducts, invade the whole 

 blood, and by degrees all the organs. Soon they swarm 

 everywhere, almost as numerous as the chemical molecules 

 in the midst of which they stir and circle. The albuminoid 

 matters are decomposed into fetid gases, escaping into the 

 air. The fixed salts, alkaline and earthy-alkaline, slowly 

 release themselves from the organic matters with which 

 they combined to form the tissues. The fats oxidize, and 

 grow acrid ; the moisture dries away. Every thing volatile 

 vanishes, and, at the end of a certain time, nothing remains 

 save the skeleton, but a formless mingling of mineral prin- 

 ciples, a sort of humus, ready to manure the earth. Now, 

 all these complex operations absolutely required the in- 

 tervention of the infusoria of putrefaction. In pure air, 

 deprived of living germs, they could not have been accom- 

 plished. To check putrid fermentations, to insure the con- 

 servation of animal or vegetable substances in a state of 



