82 THE ROYAL SOCIETY OF CANADA 



These experiments give a curve for muscle somewhat similar to 

 that for the intact animal, at a slightly higher temperature level, 

 while data obtained from observations on the surviving tissues in the 

 longer experiments in series II give points on this curve. 



The death point of peripheral nerve (as indicated by electrical 

 stimulation in cases where the muscle survived) is one or two degrees 

 lower than that of striped muscle. 



It would seem possible that the cause of death in muscle sub- 

 jected to moderately high temperatures (25° to 35 °C.) for a few hours 

 is not protein coagulation, since there is in almost all cases no trace 

 of heat rigor, the muscles remaining soft and translucent (compare 

 also experiment 55, series II). 



DISCUSSION OF RESULTS. 



Experiments on the intact animal in air and in water indicate a 

 certain degree of variation in the effect of continued exposure to 

 definite temperatures. This is shown especially in the experiments 

 in air, in which the animals were kept for one hour at 31° and at 32°. 



The experiments in air lead to the unexpected conclusion that 

 the highest temperature at which R. pipiens can maintain life in- 

 definitely is about 18°C. while a temperature a degree or two higher 

 will prove fatal within a few days. The fatal temperature is to a 

 great extent a function of time, varying from 19° or 20° to 39° or 40° 

 as the time is shortened. Allowing for the slight individual variations 

 mentioned, the effect is specific. Further, recovery, when un- 

 consciousness intervenes, occurs within two or three hours, or not 

 at all. 



The cause of somatic death cannot be stated. The heart, specific 

 effect on which might be regarded as most likely to be the cause, has 

 been shown to be functioning in numerous cases where somatic death 

 has occurred. Brain, nerve, and muscle are apparently normal 

 after somatic death. Injury to other organs would probably not 

 result in immediate death, but in death after partial recovery. Such 

 delayed results were not obtained in any of the experiments of short 

 duration (one or two hours). 



A possible cause of death might be laking of blood, with resulting 

 absorption of haemoglobin and a toxic effect thereform (this was 

 suggested to us in discussion by Dr. A. Gibson). This seems pre- 

 cluded by the fact that in a number of experiments blood-corpuscles 

 were seen moving in the vessels in the web of the foot, though somatic 

 death had occurred (see experiments 11, 25, 44), and particularly 

 by the results in experiment 58, where after somatic death, microscopic 

 examination of the blood revealed no abnormality. 



