722 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



different doses of conia obtained from that chemist, occur also with different doses 

 of hydrochlorate of methyl-conia. 



Experiment LXXXVIII. — Immediately after ligaturing the blood-vessels at 

 the upper part of the right thigh in a frog, weighing 140 grains, we injected a 

 solution, containing one-tenth of a grain of hydrochlorate of methyl-conia, under 

 the skin at the left flank. In thirteen minutes, the frog was flaccid, and no 

 voluntary movements occurred in the poisoned region ; but vigorous movements, 

 consisting of extreme and somewhat spasmodic extensions, occurred at frequent 

 intervals in the right (non-poisoned) posterior extremity. Irritation of the skin 

 in the poisoned region now caused merely feeble twitches in the left (poisoned) 

 posterior extremity, and energetic movements in the right posterior. In fifty 

 minutes, however, no reflex movement could be excited anywhere by irritation 

 of the skin. The left sciatic nerve was exposed and subjected to galvanic 

 stimulation, with the result that, while well-marked movements occurred in the 

 left posterior extremity, no movement occurred in the right (non-poisoned). It 

 was at the same time ascertained that the motor conductivity of the right sciatic 

 nerve was not appreciably impaired, even in that part of the trunk exposed to 

 the direct action of the poison ; that the poisoned muscles retained their con- 

 tractility ; and that the heart was contracting, in normal rhythm, at the rate of 

 twenty beats per minute. Several observations were made during the succeeding 

 fifty minutes, but no change had occurred during this time, with the exception 

 of a slight diminution in the rate of the heart's contractions. 



On the following morning, the frog was dead. 



Experiment XCL — The blood-vessels were tied at the lowest third of the 

 right thigh of a frog, weighing 200 grains, and two-tenths of a grain of hydro- 

 chlorate of methyl-conia, dissolved in four minims of distilled water, was then 

 injected under the skin at the left flank. The first symptom that was observed 

 occurred in three minutes, and consisted of a stiff extension of the anterior 

 extremities, causing unnatural elevation of the thorax. After a few seconds, 

 this symptom was modified to the extent that the anterior extremities became 

 rigidly incurved, with the fore-paws in contact with each other. Vigorous jump- 

 ing movements were still attempted, but as the anterior extremities took no part 

 in these, they were very imperfect, and frequently resulted in the frog falling on 

 one side. In ten minutes, this spasmodic condition of the anterior extremities 

 disappeared, and now the frog lay flaccid on the lower jaw, chest, and abdomen. 

 The power of voluntary movement seemed to be suspended in the poisoned 

 region, but it was retained in the non-poisoned (right posterior extremity), where 

 vigorous and somewhat spasmodic movements of extreme extension frequently 

 occurred. In thirty-three minutes, irritation of the skin caused energetic reflex 

 movements in the right posterior extremity, but no movement in any part of the 

 poisoned region. In thirty-four minutes, the left sciatic nerve was exposed, and 



