nourishing and growing portion. Many of them, indeed, have curious instincts, 

 and perform labours in which a great deal of what we would call ingenuity, if 

 they were the results of contrivance, is displayed. The cells of the bee, the webs 

 of the spiders, the nests and covert-ways of the white ants, and a countless num- 

 ber of others, might be mentioned in proof of this ; but the animals which per- 

 form those curious labours display no more sagacity and resource than the hum- 

 blest of the whole. The bee or the spider, for example, does not display more 

 sagacity than the common earthworm, which is, perhaps, the most sentient of the 

 three ; and yet it has no visible organs of localized senses. This, by the way, is a 

 pretty convincing proof that sensation is the result of the organization taken gene- 

 rally, and not of any particular part of it ; though there is no doubt that any par- 

 ticular modification of sense must be acute in proportion to the perfection of its 

 organ. 



The vertebrated animals are as evidently founded upon the nervous system. 

 It is the first organic portion which can be traced in the embryo when little else 

 than a gelatinous mass ; and in that part of it which may be considered as central, 

 and as such productive of the nervous energy, it is everywhere so fenced in and 

 protected by bones, as that none of the other systems, and more especially the me- 

 chanical system, can in the least interfere with it. In the invertebrated animals 

 the case is very different ; the nervous system is, in its central and essential parts, 

 mixed up both with the vital and the mechanical system, and it is subservient to 

 them. We can easily understand from the structure of man and of the higher 

 orders of vertebrated animals, that the nervous system, in order to work to the 

 full degree of perfection of which it is susceptible, must work perfectly alone and 

 undisturbed ; and though it is impossible for us to say what specific effect this 

 system has on the ultimate action of the animal as a whole, yet as that is always 

 superior in proportion as the nervous system is developed, we must conclude that 

 this system is a most essential part. Another opportunity will be afforded in a 

 future number of The Naturalist, for investigating the curious connexion which 

 there appears to be between the nervous energy of animals and that general 

 energy of matter, whether organized or not, which is known by the several names 

 of caloric, electricity, and galvanism, and conversely by the name of magnetism. 

 But we may, in the mean time, remark that those animals and parts of animals 

 which are capable of the most powerful action, how brief soever may be its dura- 

 tion, are also the most susceptible to electric excitement. 



This protection afforded to the centre of the nervous system in the vertebrated 

 animals, is obtained at some sacrifice of effect in proportion to exertion in the me- 

 chanical system ; and the sacrifice is always the greater the more that the nervous 

 system is developed and protected. It is greater in mammalia than in birds ; 

 greater in birds than in reptiles ; and greater in reptiles than in fishes : and it is 

 greatest of all in the cartilaginous fishes, which, though superior to common fishes 



