The term circulation is not strictly applicable to the imperfect sanguineous system of insects, as the fluid which supplies their bodies with nutriment is not distributed to its several parts through the medium of a heart and vascular system. Lyonnet and Cuvier are both of opinion that insects have no heart, whereas all creatures that possess a circulation, properly so called, have a heart, lungs or gills, and a liver; but insects have only air-vessels and hepatic ducts. The chyle which is produced in their intestines, transpiring through the pores of the intestinal canal, passes into the general cavity of the body, where it is probably animalized, and made to answer the same purposes that blood does to creatures of a higher class, though when animalized it still retains its white colour. Although its distribution is obscure, from its analogy to blood, we may conclude that it is a fluid which visits and nourishes every part of the insect's body; that from it secretions are made, and that, as in other creatures, it is fitted for these purposes by receiving oxygen from the air-vessels. +Cuvier+ has observed that the blood of insects, "for want of a circulating system, not being able to seek the air, the air goes to seek the blood;" the air-vessels, as I have stated under the head of Respiration, are distributed to every part of the body. +Nutrition.+ From what I have said under the head of Circulation, it will appear evident that the bodies of bees and other insects are supplied with nutriment in a very simple manner. +Cuvier+ is of opinion that it is obtained by direct absorption or transudation, by imbibition as he calls it, through the pores of the intestinal canal, along which the blood or animalized chyle passes: and +Lyonnet+ thinks that this imbibition is analogous to that which takes place from the earth by the roots of plants. +Secretion.+ Every thing connected with the subject of secretion seems to be obscure: it is evident, however, that secretions do take place; for silk, wax, and poison are all the results of that process. The first of these substances is only secreted by the bee when in its larva state. I must refer those who wish for information respecting silk, to those naturalists who have written on the silk-worm. The secretion of wax I shall treat of hereafter in a distinct chapter; and it will be better perhaps to speak of Poison, after describing the sting and its appurtenances. There is one secretion however, on which I will say a few words in this place,--viz. Perspiration. +Perspiration.+