Does a Fatigue Toxin Exist? 



153 



have also been noted by other observers after excluding the 

 pancreatic juice from the gut. 



None of our dogs showed polyuria; 580 c.c. was the largest 

 recorded daily output. Acetone was seen only exceptionally. 



All of the dogs showed an initially rapid and then slowly pro- 

 gressive loss of weight. Thus No. 5 lost 3.25 kilos in 12 days, but 

 during the next 90 days lost only a little more than one kilo. 



The experiments are being continued. 



91 (1269) 



Does a fatigue toxin exist? 



By Frederic S. Lee and B. Aronovitch. 



[From the Department of Physiology, Columbia University, New 



York.] 



In 1904 Weichardt claimed to have found a specific substance, 

 a fatigue toxin, as the chief agent in the production of fatigue. 

 When present it was capable of forming in the tissues its own 

 antidote, an antitoxin. A substance identical with fatigue toxin, 

 named "kenotoxin," was obtained in vitro by treating proteins 

 in various ways. However obtained, the substance, when injected 

 into animals in small quantity, resulted in the production of 

 antitoxin; when in larger quantity, it caused a great reduction in 

 bodily temperature, slowing of respiration, sleep, and ultimately 

 death. 



In the present experiments animals, such as rabbits or cats, 

 were fatigued by running in a revolving wheel. After fatigue was 

 pronounced the animals were killed by decapitation, and the 

 muscles of the hind legs were stimulated directly by the faradic 

 current until they ceased to contract. Soon after death, in some 

 cases within six to eight minutes, marked rigor was observed in 

 the skeletal musculature. Immediately after the cessation of 

 response to faradic stimulation the muscles of the hind legs were 

 removed, cut to pieces and ground thoroughly with sand, and the 

 muscle juice was squeezed out by a powerful press, all procedures 

 being carried on with aseptic precautions. The juice was found 

 markedly acid to litmus. When this juice was injected into the 



