154 



Scientific Proceedings (84). 



peritoneal cavity of guinea pigs, usually in quantities as large as 

 10 c.c., either at the temperature of the room or after being warmed 

 to bodily temperature, the animal became quiet; there was no 

 constant effect on respiration, which sometimes increased in rate 

 and sometimes decreased; and the bodily temperature began to 

 fall at once. The fall continued during 30 minutes to 1 hour, the 

 maximum so far observed being i.6° C, after which there was a 

 slower return toward the original temperature. These are the 

 only immediate effects that have been observed. Occasionally the 

 animal died on the following day. Precisely the same effects, 

 including occasionally death on the next day, were obtained when 

 the muscle juice of non-fatigued animals was used. 



The working power of excised gastrocnemius muscles of the 

 frog, when suspended in a bath of muscle juice prepared from 

 fatigued and non-fatigued cats respectively, was studied. With 

 the juice from fatigued muscles the duration of the working 

 period of the gastrocnemii and the total amount of work per- 

 formed were each diminished by about one half when compared 

 with normal muscles not treated with juice. Practically the same 

 quantatitive effect was observed when the gastrocnemii were 

 treated with non-fatigued juice. 



There can be no doubt that by the methods employed above, 

 the muscles were thoroughly fatigued. The conclusion seems 

 justified that no acutely toxic fatigue substance was produced. 

 Weichardt's assumption of the existence of a specific fatigue 

 toxin is therefore not sustained. It seems probable that Weich- 

 ardt's animals, which were actually killed by his extreme methods 

 of inducing fatigue, were put into a profoundly pathological 

 condition in which the toxic component of the protein molecule 

 was split off. There is no reason to believe that this occurs in the 

 normal course of fatigue. 



