708 FRANCIS H. McCRUDDEN 



contractions, but to metabolic activities as well. Thus, throughout a period 

 of years, despite great variation in the rate of heat loss, and in the supply 

 of fuel, the body temperature is constantly maintained at the optimum 

 temperature for physiological activities ; and with great and rapid varia- 

 tions in the supply of carbohydrate in the food, on the one hand, and in 

 the rate of carbohydrate catabolism on the other, the blood continues to 

 maintain an even level of one-tenth of one per cent sugar. The very 

 complex activities of various organs and functions, whereby constancy in 

 the body temperature and blood sugar is maintained, are coordinated 

 through the nervous system. 



The changes in the metabolism in diseases of the nervous system re- 

 sult from failure of coordination. Through failure to adapt activities to 

 needs, the activities become purposeless. After certain changes in the 

 nervous system, the maintenance of normal heat regulation, and normal 

 sugar may fail. When physiological connection between the nervous sys- 

 tem and voluntary muscle is broken by the administration of curare, a 

 mammal will lose the power of maintaining its body temperature constant 

 (Rochrig and Zuntz). Even after such a relatively simple operation as 

 puncture of the floor of the fourth ventricle, hyperpyrexia and hypergly- 

 cemia may arise. Similarly, in the case of bone metabolism : the struc- 

 ture and composition of the bone is determined by the needs ; the plates 

 of concelli are laid down along the lines of stress and strain, and shift 

 with change in these lines; and where through disuse the stresses and 

 strains become very slight, rarefaction of the bone results. The cen- 

 tripetal impulses in this case result from the pulls on the muscular ridges 

 and the pressure on the articulating surfaces of the joints. When the 

 continuity of the arc for deep reflexes is broken, as in tabes and syringo- 

 myelia, there is a failure of coordination .leading to the formation of 

 structureless bone ; the bone metabolism "runs wild" and gives rise to the 

 "Charcot joints." 



Pathological changes in the nervous system may then lead to dis- 

 turbances in the metabolism of any organ, function or compound. Such 

 disturbances may be discussed either as disease of the nervous system, or 

 as disease of the organ, or function, or compound in question. Thus, in 

 the case of Charcot joints, and glycosuria of nervous origin, we can dis- 

 cuss the metabolism in both cases under nervous disease; or we can 

 discuss one under bone disease, and the other under carbohydrate metabo- 

 lism. With the' exception of disturbances in the metabolism of the muscles 

 it is more satisfactory, however, to discuss such disturbances under dis- 

 ease of the organ, 'or function, or compound in question, and they are so 

 discussed in this book. In the present state of our knowledge, it is more 

 satisfactory to discuss the metabolism of diseases of the muscles, and . 

 nervous diseases which involve muscular metabolism together, as disease 

 of the neuromuscular system. 



