124 On the Temperature of the Spider ; and on the 



same spider, taking precautions which I suggested to him, 

 he found the thermometer under the abdomen, and in con- 

 tact with it, from one-half to three quarters of a degree 

 higher than in the air of the box in which the spider was 

 confined ; and he stated that the same results followed the 

 experiment when made at different atmospheric tempera- 

 tures. These last results, of course, I consider, as did also 

 Mr Longmore, the most accurate. 



In connexion with its temperature, I have thought it worth 

 while to ascertain the proportion of carbonic acid formed by 

 the spider in a certain time. The spider, the temperature 

 of which I had ti'ied, was confined in a glass jar, over water 

 of the capacity of 23 cubic inches, and holding this quantity 

 of common air. After 24i- hours, (tlie temperature of the 

 room the same at the beginning and end of the experiment), 

 calculating the absorption that had taken place, the dimi- 

 nution of the volume of air, and the after diminution by agi- 

 tation with lime-water, it was found that there was a total 

 diminution of 2'11 cubic inches of air, so that about this 

 quantity of carbonic acid, it may be inferred, had been form- 

 ed. In a second experiment, on another species of Mygale, 

 about half the size of the former, after three days confine- 

 ment in 13-6 cubic inches of atmospheric air, nearly a cubic 

 inch (-97 of a cubic inch) appeared to be formed. The spider, 

 at the end of three days, was alive and active. These re- 

 sults, on the quantity of oxygen consumed by these spiders, 

 in the formation of carbonic acid, or the animal-heating pro- 

 cess, may be considered in accordance with the degree of 

 temperature they have been observed to possess. 



I have mentioned, that the spider first used in the trial 

 on temperature, devoured the soft parts of a beetle : of this 

 I satisfied myself by careful examination of the remains. 

 And, I may add, that from repeated observations, I am sure, 

 that spiders do not, according to popular belief, feed on the 

 juices of the animals they make their prey, but on their 

 muscle and other soft parts. The same remark, the result 

 also of observation, applies to the scorpion. 



As regards this last mentioned animal, there is another 

 popular belief, which I have no doubt is equally ill-founded, 



