64 RESPIRATORY EXCHANGE OF ANIMALS AND MAN 



but by no means regularly (Anderson and Bergmann [1898]), causes a 

 pronounced increase in standard metabolism (Magnus-Levy [1895]). 

 In patients suffering from exophthalmic goitre the respiratory ex- 

 change is increased compared with normal (Magnus-Levy [1895], 

 Undeutsch [1913]) and may reach 8 c.c. of oxygen per kilogram and 

 minute or double the normal (Hirschlaff [1899]). 



Magnus-Levy points out that the nature of the effect of the thyroid 

 gland is difficult to ascertain. In exophthalmic goitre muscular shiver- 

 ings and restlessness are important symptoms which are never absent 

 in severe cases. In Magnus-Levy's experiments no visible movements 

 occurred, but nevertheless the possibility that we have to do with an 

 effect on muscular activity (or tone) cannot at present be excluded. 

 Experiments ought to be made on animals on which curari could be 

 used to suppress any influence upon the muscular activity, but an in- 

 crease of the true basal metabolism can be demonstrated only if it can 

 be shown that the thyroid has no influence upon the muscular tone. 



The Hypophysis. 



Benedict and Romans [1912] have studied very carefully the effects 

 of hypophysectomy on dogs. They made use of the recording cage 

 described above (p. 15) and selected for comparison only such periods 

 during which the animal remained quiet. There is no doubt therefore 

 that their comparisons are valid and represent standard conditions. The 

 day to day variations in metabolism are, however, remarkably large. 

 They found that some days after the removal of the hypophysis the 

 metabolism and pulse-rate decreased, in most cases considerably. In 

 young animals the growth stopped and a tendency to deposition of 

 fat developed gradually. The metabolism remained low until, shortly 

 before death, a large drop in metabolism and body temperature took 

 place. 



The Sexual Glands. 



The effect of the sexual glands upon basal metabolism is even 

 more doubtful than that of the thyroid, though a certain effect 

 upon standard metabolism has been observed both on dogs and on 

 man. 



Loewy and Richter [1899] found in experiments on a male dog 

 that castration produced after an interval of eleven days a distinct de- 

 crease in the respiratory exchange " when the dog was lying absolutely 

 quiet". Though the weight of the dog decreased, the oxygen per 



