Scientific Proceedings. 



(I2i) 57 



The following results extend the observations reported by 

 Brown and Sollmann : 



1. In frogs weighing about 25 gm. no effect was observed after 

 introduction per os, when less than 40 mg. was introduced. This 

 amount caused only slight symptoms. Subcutaneous injection of 

 40 mg. caused death in about 60 hours. Injection of the same 

 amount per rectum appeared to be more quickly followed by toxic 

 results than when introduction occurred through either of the 

 former channels. Introduction per os caused irritation of the 

 throat, increased gastric secretion, ejection of gastric contents and 

 increased peristalsis. It required per os approximately 1 . 5 gm. per 

 kilo to produce general toxic results, among which were anhi- 

 drosis, twitching, and progressive weakening of the muscles, with 

 paralysis of the forelegs preceding paralysis of the hind ones. In 

 fatal cases the reflexes were abolished in the usual order. The 

 general toxic effects after introduction subcutaneously or per rec- 

 tum were about the same as those following introduction by way 

 of the stomach. 



2. In warm-blooded animals (mice and dogs) relatively large 

 doses administered subcutaneously caused restlessness, twitching 

 of the muscles, progressive paralysis, labored breathing, stupor, 

 death. Paralysis of fore-legs preceded loss of power in the hind 

 legs. Injection of 5 gm. of the chlorid into a dog weighing 1 5 

 kilos failed to cause death. Ingestion of 2 gm. with 100 gm. of 

 meat, by a dog weighing 6 kilos, was followed in two hours by 

 vomiting. The ejected matter was gradually eaten during the 

 next few hours with no other apparent effect thereafter than loss 

 of appetite and increased desire for water. 



3. The most constant and pronounced general effect of the 

 tetrachlorid of thorium was a progressive weakening of all the 

 voluntary muscles. 



Eleventh meeting. 1 



• Zoological Laboratory of Columbia University. April 19, 1905. 

 President Wilson in the chair. 



25 (71). "The relation between normal and abnormal devel- 

 opment of the frog's egg " : T. H. MORGAN. 



The method of development of the frog's egg may be changed 



1 Reprinted from Science, 1905, xxi, p. 741 ; American Medicine, 1905, ix, p. 

 744 ; Medical A T ezvs, 1905, lxxxvii, p. 87. 



