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whose pleasure it is to try and enter sympathetically into the conditions and capacities of all living things will be greatly interested in an account which, of Sophia, has published of his experiments on the temperature of insects. This account tells us in a clear and masterly manner 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 consideration 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 generated, 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