122 Relations of the Structure of 



In this research, Professor Grant, hi his admirable lectures 

 at the London University, and Mr. Newman, in his letters on 

 the Osteology of Insects, in the Entomological Magazine, have 

 both preceded me; but, by restricting myself to much narrower 

 limits than the former, and avoiding altogether the tech- 

 nicalities of the latter, I trust it will not be difficult to steer a 

 middle course, without the least interference with either of 

 them. 



Animals are termed annulate, from having the exterior of 

 their bodies divided into rings. The name may be considered 

 as applicable to every creature commonly known as an insect; 

 flies, bees, wasps, beetles, grasshoppers, dragon-flies, moths, 

 butterflies, fleas, mites, spiders, centipedes, scorpions, lob- 

 sters, crabs, shrimps, &c., &c. 



In these creatures we find the seven principal systems of 

 organs observable in larger animals and in man : the organs 

 of sensation, or nervous system; the organs of support, os- 

 seous or bony system ; the organs of motion, or muscular 

 system; and these three we shall find, throughout their varied 

 developement, peculiarly connected and dependent on each 

 other : the organs of circulation, or vascular system ; the 

 organs of respiration, or respiratory system ; these two, also, 

 being dependent on each other : the organs of nutrition, or 

 digestive system; and the organs of reproduction, or generative 

 system. 



We frequently find, in the writings of men entitled to the 

 greatest respect, a kind of triple division made of the organs 

 of sensation — the brain, the nerves, and the organs of the 

 senses. Let us examine whether this division really exists. 

 Vegetable physiologists have shown that the delicate flowers 

 of a plant are but the perfected continuation and completion 

 of the same rind which originates in the root and clothes the 

 stem. Now, it appears to me, that the nerves originate in 

 the brain, which is their root, branch through the body, and 

 blossom in the organs of the senses ; and that, therefore, each 

 peculiar character they assume is but the modification of the 

 same system. Taste, smell, hearing, and sight must, in this 

 case, be considered as nothing more than variously perfected 

 attenuations of the same nerves which are distributed through- 

 out the body; in other words, varied developements of the 

 power of feeling, wonderfully contrived to arrest, ascertain, 

 and apply the properties of substances, effluvia, sounds, and 

 rays of light. The nerves, when terminating simply in organs 

 of sensation, appear to be endowed with a double capacity : 

 they convey the impression of the presence and form of inert 



