The Endocrine System 239 



organism can no longer remove the carbon dioxide and "air hunger" 

 follows. 



Other dangerous complications accompany diabetes. One of these 

 is arteriosclerosis or hardening of the arteries. This is particularly 

 prevalent in the arteries of the legs and arms, and may render them 

 more susceptible to gangrenous infections. On the whole, the diabetic 

 individual is more susceptible to bacterial infections, tooth decay, and 

 even eye defects. 



It has never been clearly demonstrated that diabetes can be caused 

 by dietary excesses. More important apparently is the fact that there 

 is some inheritance of carbohydrate tolerance. Also, diabetes is often 

 correlated with obesity and is found more frequently among nervous 

 individuals. Statistically it can be shown that it occurs more often 

 among city dwellers than among rural inhabitants. 



Fortunately the chances of surviving with diabetes are excellent. 

 There must be some care with the diet in order to decrease the intake 

 of carbohydrates. Of course, most important is the fact that other 

 sources of insulin are available. The insulin, however, must be in- 

 jected for the enzymes of the digestive system destroy the proteins 

 which make up the insulin molecule. For effective use, it is desirable 

 that the insulin be in such a combination that it is released slowly over 

 a period of time. Since 1936, a form known as protamine insulin has 

 become available. This is an insulin compound which liberates very 

 slowly in the tissues. When this is combined with zinc, the action is 

 further prolonged. 



The Effects of Hyperactivity. — Occasionally tumorous conditions 

 of the islet tissue result in excessive secretion of insulin, and the 

 condition known as hyperinsulinism develops. In this disease, the blood 

 sugar level is much reduced. Inasmuch as the central nervous system 

 is very sensitive to this reduced level, the effects may be traceable to 

 this change. At first, extreme hunger, pallor, and cold perspiration 

 are experienced. This is followed by impairment of the senses and 

 finally convulsions and coma. Relief can be temporarily affected by 

 the administration of glucose. 



Occassionally this condition occurs in a diabetic patient who has 

 injected too much insulin. 



The Action of the Islets in Other Animals. — Many other ani- 

 mals besides mammals have been studied in this regard. It has been 

 shown that the symptoms of pancreatectomy are quite similar in birds, 



