When I asked the relatives of Mde. Robineau if they could tell me of any special circumstance which in their opinion had contributed to the extreme duration of the life of this old lady, they replied as follows:—“We are convinced that a slight bodily derangement, present for the last fifty years, has tended to prolong the life of the old lady. It cannot be said that she has suffered from diarrhœa, but she has been often subject to frequent calls of nature.” It was most remarkable that the old lady showed no traces of sclerosis of the arteries. I may mention the strongly contrasting case of one of my old colleagues to whom a natural desire to empty the bowels came only once a week. A more frequent call was a sign of illness in his case. Now sclerosis of the arteries appeared in so marked a form that he died from it before he had reached the age of fifty years. This may be added to the list of facts which point to a close association between sclerosis of the arteries and the functions of the digestive tube.
Recently, at the suggestion of Mr. Fletcher,[126] the advantage of eating extremely slowly has been recognised, the object being to prepare for the utilisation of the food materials, and to prevent intestinal putrefaction. Certainly the habit of eating quickly favours the multiplication of microbes round about the lumps of food which have been swallowed without sufficient mastication. It is quite harmful, however, to chew the food too long, and to swallow it only after it has been kept in the mouth for a considerable time. Too complete a use of the food material causes want of tone in the intestinal wall, from which as much harm may come as from imperfect mastication. In America, where Fletcher’s theory took its origin, there has already been described under the name of “Bradyfagy” a disease arising from the habit of eating too slowly. Dr. Einhorn,[127] a well-known specialist in the diseases of the digestive system, has found that several cases of this disease were rapidly cured when the patients made up their minds to eat more quickly again. Comparative physiology supplies us with arguments against too prolonged mastication. Ruminants, which carry out to the fullest extent Mr. Fletcher’s plan, are notable for extreme intestinal putrefaction and for the short duration of their lives. On the other hand, birds and reptiles, which have a very poor mechanism for breaking up food, enjoy much longer lives.
Prolonged mastication, then, cannot be recommended as a preventative of intestinal putrefaction any more than the surgical removal of the large intestine or the disinfection of the digestive tube. The field lies open for other means which may probably solve the problem more completely and more practically.
V
LACTIC ACID AS INHIBITING INTESTINAL PUTREFACTION
The development of the intestinal flora in man—Harmlessness of sterilised food—Means of preventing the putrefaction of food—Lactic fermentation and its anti-putrescent action—Experiments on man and mice—Longevity in races which use soured milk—Comparative study of different soured milks—Properties of the Bulgarian Bacillus—Means of preventing intestinal putrefaction with the help of microbes
At birth the human intestine is full, but contains no microbes. Microbes very soon appear in it, because the meconium, the contents of the intestines of new-born children, composed of bile and cast-off intestinal mucus cells, is an excellent culture medium for them. In the first hours after birth, microbes begin to reach the intestine. In the first day, before the child has taken any food whatever, there is to be found in the meconium a varied flora, composed of several species of microbes. Under the influence of the mother’s milk this flora is reduced and comes to be composed almost entirely of a special microbe described by M. Tissier and called by him Bacillus bifidus.
The food, therefore, has an influence on the microbes of the intestine. If the child be fed with cow’s milk, the flora is richer in species than in the case of a child suckled by its mother. Later on, also, the flora varies with the food, as has been proved by MM. Macfadyen, Nencki, and Mde. Sieber in the case of a woman with an intestinal fistula. The dependence of the intestinal microbes on the food makes it possible to adopt measures to modify the flora in our bodies and to replace the harmful microbes by useful microbes. Unfortunately, our actual knowledge of the intestinal flora is still very imperfect because of the impossibility of finding artificial media in which it could be grown. Notwithstanding this difficulty, however, a rational solution of the problem must be sought.
Man, even in the savage condition, prepares his food before eating it. He submits much of it to the action of fire, thus notably lessening the number of microbes. Microbes enter the digestive tube in vast numbers with raw food, and in order to lessen the number of species in the intestines, it is important to eat only cooked food and to drink only liquids that have been previously boiled. In that way, although we cannot destroy all the microbes in the food, because some of them can withstand the temperature of the boiling point of water, we can kill the great majority of them.