548 OLD AGE. 



snv. until after the destruction of all or a lar^e i)art of the microbes 

 that they contain. This measure, together Avith the use of water that 

 has been boiled, will prevent, once for all, the penetration into our 

 body of wild microbes whose injurious effects can not be denied. 



Thanks to the means we have just outlined, as well as to others 

 which we may add thereto later on, we may in the future transform 

 our intestinal flora, now so varied and uncultivated, into a flora of 

 much fewer species, exempt from injurious microbes but containing 

 useful ones — in a word, into a cultivated flora. 



But independently of this prospect, it is possible to avoid the dis- 

 advantages of our present intestinal flora by specific serums, prepared 

 Avitli a vieAv- to neutralizing the injurious action of certain microbic 

 poisons and of destroying the microbes themselves. 



As, according to our hypothesis, these microbes act upon our organ- 

 ism by weakening our noble elements and stimulating their adver- 

 saries, the macrophages, it will be rational to seek the means for rein- 

 forcing the former. The weakening- of the latter can not be 

 considered for the moment, as the macrophages are of great use to us 

 in the struggle against several infectious diseases, and notably against 

 the most terrible of all, tuberculosis. 



The idea of reinforcing our noble elements is based upon the study 

 of certain poisons called cytotoxines. Not being able to enter into 

 the details of this question we will content ourselves with remarking 

 that, while strong doses of these poisons destroy our cells, minute 

 doses, on the contrary, reinforce them. We should, then, attempt to 

 assist our noble elements in their struggle against the macrophages 

 by the aid of cytotoxines. This problem is complex and delicate, and 

 requires numerous preliminary researches of long duration. These 

 were begun a year ago. At this time the question is not sufficiently 

 mature for any kind of discussion. 



The theory of old age and the hypotheses which are connected with 

 it may be sunnnarized in a few words; the senile degeneration of our 

 organism is entirely similar to the lesions inducecf by certain nuiladies 

 of a microbic origin. Old age, then, is an infectious chronic disease 

 which is manifested by a degeneration, or an enfeebling of the noble 

 ehMuents, and by the excessive activity of the niacropliages. These 

 modifications cause a disturbance of the equilibrium of the cells com- 

 posing our body and set up a struggle within our organism which 

 ends in a precocious aging and in premature death, contrary to 

 nature. 



It is very probable that during the time we are growing old the 

 intestinal microbes that have set up within our body permanent fac- 

 tories for different poisons play a very important part. It is, then, 

 entirely possible to struggle against premature senility by modifying 



