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THE TEMPERATURE OF INSECTS. 

 By Geoffrey Smith. 



Naturalists whose pleasure it is to try and enter sympa- 

 thetically into the conditions and capacities of all living things 

 will be greatly interested in an account which Prof. Bachmetjew, 

 of Sophia, has published of his experiments on the temperature 

 of insects.* This account tells us in a clear and masterly man- 

 ner of an excursion into the field of invertebrate physiology— a 

 field too little cultivated by professed biologists, owing, it must 

 be supposed, to the great difficulties encountered, and not to the 

 innate barrenness of the land ; indeed, it seems that the problems 

 of biology, which have been so long attacked from an almost 

 purely morphological standpoint, can at this stage of enquiry 

 only be further elucidated by a wider and more searching scrutiny 

 of organs and organisms from the point of view of function. This 

 wider view of Biology is one which is likely to find favour with 

 readers of ' The Zoologist' ; and since the researches under con- 

 sideration are directed towards the advancement of knowledge in 

 this direction, and since they may not be readily accessible to all 

 naturalists, I have ventured to think that a short abstract of 

 Prof. Bachmetjew's work, with a discussion of its bearings on 

 certain problems of insect coloration, might be acceptable. 



We need not occupy ourselves for long in considering the 

 Professor's method of research ; it is essentially simple and 

 accurate. The fact is well known to physicists that when two 

 suitable metals are placed in contact an electric current is gener- 

 ated, and this current is accurately proportionate in strength to 

 the temperature of the two metallic poles. In the researches 

 which we are going to describe the metals employed were steel 

 and manganese ; the insect whose temperature was to be taken 

 was pierced by a fine needle of this composition, and the strength 



* ' Experimentelle entoniologische Studien,' von P. Bachmetjew. Leipzig, 

 1901. Erster Band. 



