Changes in the pituitary body may also be a factor in producing premature old age. It is a fact that all people suffering from acromegaly appear much older than their age. In fact, one of the first symptoms that arouses the anxiety of the relatives of such a patient is that he looks so much older, and it is only later that they notice the overgrowth of the nose, the hands, and feet. Since, in many people who are getting older, the head and nose may increase in size, we may suppose that this is the clinical expression of senile changes in the pituitary body. There is a condition known as “acromegalie fruste,” in which the symptoms are only slightly pronounced and which is often unrecognized. As we have already said, all diseases of the ductless glands may be only partially developed. This is due to the fact that only a proportion of the thousands of follicles, of which such a gland is composed, need be affected. The ovaries and testicles also show changes as an evidence of their fight against infections, and we have mentioned the findings of Professor Metschnikoff with regard to these glands. In every severe infectious disease the liver shows great change in its parenchymatous tissue, with a subsequent increase of connective tissue. The increase of connective tissue in various organs, and especially in the blood-vessels, after infectious diseases, can be regarded as an illustration of our remarks on these same changes following degenerations of the thyroid. It is a well recognized fact that atheroma can be caused by various infectious diseases, and can also be artificially produced by several infectious agents. The kidneys, through their rôle as eliminative organs, usually suffer, even more than the other glands, in the course of infectious diseases. Even a slight angina may produce an acute parenchymatous nephritis, and the more virulent the infection, the more will the kidneys suffer. Not infrequently, unknown to us, important parts of the renal tissue are lost after such infections, and a chronic nephritis may creep on insidiously. After such loss there may be proliferation of connective tissue, and the kidneys thus become unable to fulfill the most important eliminative functions in the body. Owing to this incomplete elimination, toxic substances may be retained in the body. From the above considerations we can see how important it is to guard against the risk of infection. This is often impossible, considering the billions of microbes by which we are surrounded day and night. The best precaution is to keep those organs in good working order which safeguard us against infections—i.e., the ductless glands.