But much more harmful in the production of arteriosclerosis is tobacco. According to Claude Bernard, Huchard, Basch, Oser, Isaac Adler, and Hensel, tobacco produces a constriction of the small blood-vessels. Thus nicotin, adrenalin and alcohol have similar actions, which also corresponds to the observations of Sir Lauder Brunton. We have had a great many smokers among our arteriosclerotic patients; but, on the other hand, we quote further on the cases of some great smokers who lived to a very old age as we have seen. But this latter class is not numerous. Similarly, the hygiene of the intestines is of the utmost importance, especially as poisons generated in the intestines play a leading part in causing arteriosclerosis, according to Huchard, Senator, and others. We must take great care to have a daily evacuation of the bowels, and especially to prevent flatulence, for this distention of the colon or the stomach, by carrying the diaphragm upward, may interfere with the expansion of the lungs and thus produce a mechanical hindrance to the movements of the heart and a free circulation of the blood. Those with a tendency to angina pectoris must specially avoid such dangerous courses. Hill climbing, during which not infrequently such people suffer sudden death, should also be avoided. More than from 1 to 1½ liters of liquids per day should not be allowed. ------------------------------------------------------------------------ CHAPTER XVII. THE ELIMINATION OF TOXIC PRODUCTS THROUGH THE INTESTINES AND THE IMPROVEMENT OF THIS FUNCTION. THE intestines contain billions and billions of microbes, their number increasing downward throughout the length of the intestine. The duodenum contains the least, and in some parts of it there are none at all. The presence of these bacteria is a great necessity to us, as without their assistance we could not exist, for they take an active part in intestinal digestion and help to form the intermediate substances, especially from albuminous food and fat, for our nutrition. They also assist fermentation and thus induce a better peristalsis of the intestines, by which the contents are expressed. That animals cannot exist without cultures of bacteria in the intestines is shown by the experiment of Schottelius, who demonstrated that young chickens could not thrive on a sterilized nutrition, and Nuttall and Thierfelder had great trouble in keeping their guinea-pigs alive when feeding them for a time on sterilized milk.