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Note on the Temperature of the Spider ; and on the Urinary 

 Excretion of the Scorpion and Centipede. By JOHN Davy, 

 M.D., F.R.S., LoRd. and Edin., Inspector- General of Army 

 Hospitals. 



In a former communication made to this Journal, I have 

 spoken of spiders as belonging to tlie class of cold-blooded 

 animals. Though this I believe is generally admitted as a 

 fact, I am not aware of any precise observation-s that have 

 been made and published confirming it. I am induced in 

 consequence to give the following, which, although the num- 

 ber is very limited, may in part at least supply the supposed 

 deficiency. 



The subject of the first trials I shall mention was a large 

 species of Mygale, not uncommon in Barbadoes, the body of 

 ■which was about an inch long. A small thermometer, with 

 a projecting bulb, applied to its abdomen, was stationary at 

 86-2.5° Fahrenheit, when a similar one placed under the glass 

 vessel in which the spider was confined stood at 86°. The 

 following day, the difference between the two thermometers 

 was a little greater; that in contact with the spider was 

 88-5° ; that under the glass 88°. On this occasion the spider 

 was placed on cotton-wool, and the bulb of the instrument 

 was between this bad conductor of heat and the abdomen of 

 the animal. I may add, that the previous nights it devour- 

 ed the soft parts of a beetle, and voided a considerable quan- 

 tity of urinary excrement, consisting almost entirely of xan- 

 thic oxide. The trial of the thermometer on this spider 

 was repeated several times, and with the same result. 



In Trinidad, as well as in some of the other "West Indian 

 islands, a very large spider {A. avicularia, Linn. ?) is met 

 with. At my request, Mr Longmore, assistant-surgeon of 

 the 19th regiment, stationed in Trinidad, was so good as to 

 institute some ti'ials on it, to determine its temperature. In 

 the first he made, he informed me that a delicate thermo- 

 meter, tlie bulb of \yhich was grasped by tlie spider so as to 

 be surrounded, rose in one instance from 85° to 86i° ; in an- 

 other from 83 to 85". In some other trials, made on the 



