BY II. G. CHAPMAN. 299 



When, however, the dose of strychnine was large, no spasms 

 were noted unless the frog was stimulated at frequent intervals. 

 With doses of 0*1 mg. per gm. and upwards, paralysis was com- 

 plete in 8 to 3 minutes. When no external stimulation was 

 applied, the frog was noted to gradually sink down until its 

 ventral surface became parallel to the board on which it sat. 

 The fore limbs bent up slowly as if they were unable to support 

 the weight of the body. If at this stage the frog was gently 

 turned on to its back, it made feeble efforts to return to its natural 

 posture. The efforts not infrequently caused a spasm. If the 

 frog was unable to regain the natural position it la}' quiet on its 

 back. In a few seconds stimulation would fail to produce any 

 reflex response. The movements of respiration and swallowing 

 ceased, but the heart beat was vigorous. Gradually the 

 heart beat became less, until extreme care was necessary to detect 

 it. In fact on several occasions the decision that a f rog w T as dead 

 was recorded, a decision that had to be altered when the frog 

 subsequently showed signs of life. The period of paralysis 

 endured from three to twenty-nine hours in these experiments. 

 Many frogs which died did not recover from the stage of paralysis. 

 With the majority of frogs, after a number of hours the applica- 

 tion of a strong external stimulus brought about a reflex. Soon 

 the threshold value of the stimulus was lowered so that even a 

 slight stimulus produced a wide-spread spasm. In this stage the 

 frog (Hyla) showed an appearance identical with that observed 

 in the typical convulsive stage in Rana. This stage lasted many 

 hours. In one case the spasms endured during 120 hours before 

 the frog died. Two other frogs recovered after the spasms had 

 recurred intermittently for 120 hours. Between the spasms the 

 frog lay in a paralytic condition superficially not unlike that of 

 the initial paralysis. 



In order to determine the condition of the frog during the 

 stage of paralysis, certain experiments were made on the excita- 

 bility of the muscles and nerves of the poisoned frog. 



A pithed frog, weighing 16-2 gm., received 162 mg. strychnine 

 as sulphate dissolved in 0*33 c.c. salt solution. Four minutes 



