found that many poisons act upon animal heat so as to diminish 

 it considerably. Demarquay and Dume'ril, junior, and later, 

 these two experimenters, joined with Lecointre, have found the 

 same thing as Brodie in many toxic agents. I have made 

 very numerous experiments on this subject, and some of their 

 results have been published before the last papers of Demarquay, 

 Dume'ril and Lecointre.* 



I have stated that many poisons, either injected in the veins 

 or absorbed by the vessels of the skin or of the digestive canal, 

 may diminish sufficiently the temperature of Guinea pigs 

 and rabbits, to produce death. This occurs when the dose of 

 the poison is not large enough to kill in less than four or 

 five hours. These poisons may kill only by their action upon 

 animal heat. It may be so with opium, cyanhydric acid, the 

 cyanide of mercury, hyoscyamus, digitalis, belladonna, tobacco, 

 euphorbia, camphor, alcohol, acetic, oxalic, sulphuric, azotic, 

 chlorohydric acids much diluted, and some oxalates. 



Of course the action of these poisons is the greater, the colder 

 the atmosphere ; but it is not always immediately so, and in- 

 stead of diminishing the animal heat, many may increase it 

 for a time, especially when the temperature of the atmosphere 

 is elevated. 



I have discovered that a dose of one of these poisons, suf- 

 ficient to kill an animal, when there is no obstacle to the dimi- 

 nution of its temperature, may be unable to destroy life when the 

 temperature of the animal is maintained by artificial means to 

 its normal degree, or not far from it. My experiments have 

 been conducted as follows : 



Equal doses of poison were given, simultaneously, to two ani- 

 mals, as much alike one another as possible. One of them 

 was left in a room at a temperature of from 46 to 50 F. (8 to 

 10 Cs.), and the other was kept not far from a chimney, in a 

 place where the air was at from 75 to 86 F. (24 to 30 Cs.) 

 The first was dead after a certain number of hours, or sometimes 

 one or two days, having its temperature much diminished. The 

 other, on the contrary, had no perceptible diminution of its 

 temperature, and was generally cured very soon. Therefore, 



* See Gaz. Med. de Paris, 1849, t. iv., p. 644. 



