'242 Mr. Brayley on the Dhtrihution in the Animal Kingdom 



that the miscellaneous papers should be delivered in and read 

 to the meetings in an abbreviated form, ready for immediate 

 publication. 



Should the original transcript read at Cambridge happen 

 to have remained in the hands of any member of the Section 

 of Natural History of 1833, the author will feel obliged by its 

 being returned to him. 



London Institution, Feb. 7, 1835. 



On comparing and classifying the facts constituting our 

 present knowledge of those functions of the animal ceconomy 

 which are connected, respectively, with the production of heat 

 and Hght, as existing, in their various gradations, throughout 

 the animal kingdom, certain laws have appeared to the author 

 to regulate the distribution of those functions. The complete 

 verification of these laws will require the ascertainment of a 

 great number of new facts ; comprising observations on the 

 natural temperature of many species among vertebrated ani- 

 mals, and of the amount or intensity of the tight emitted by a 

 large majority of the marine invertebrated animals and a few 

 insects ; as well as some very delicate researches on the tem- 

 perature of certain species of each division not hitherto re- 

 garded as having the power of maintaining a temperature 

 higher than that of the medium in which they live. The 

 chief object of the author, therefore, in the memoir of which 

 the present notice is intended as a brief Prodromus, is to an- 

 nounce, as approximations, the natural laws in question, and 

 to draw to these subjects the attention of men of science ; espe- 

 cially of physiologists and of scientific travellers, on the latter 

 of whom the demonstration of them will in great measure 

 rest; the author acknowledging his inability at present fully 

 to verify the laws, the future demonstration of which he never- 

 theless ventures, with some confidence, to predict. 



In referring to the production of heat by animals, the 

 author means what is commonly understood by the term ani- 

 mal or vital heat, — the result of the power of maintaining, in 

 the living body and as a consequence of life, a temperature 

 independent of that possessed by the medium in which the 

 animal is immersed, or by the substances with which it may 

 be in contact. 



In referring to the production of light by animals, the 

 author means what has been termed by Professor Macartney 

 animal light*, — the result of the power of becoming luminous, 

 as a consequence of life, and as manifested by the animals 



* Philosophical Transactions for 1810, p. 289. 



