ON THE STRUCTURE OF OSCILLATORIiE. 255 



animals which are devoid of a nervous system, whether con- 

 sisting of a spinal cord or a system of ganglions. Thus, in some 

 of the Radiata, for instance, every trace of a nervous system has 

 disappeared, yet I am not aware that they are devoid of sen- 

 sibility, though without nerves. Nor would it avail much to 

 say, though we are not able to demonstrate its existence, yet it 

 may, nevertheless exist, as this argument would be equally 

 applicable in reference to plants. The existence of nerves as 

 special organs in certain classes of animals, must, therefore, 

 be regarded as an instance of that general law which may be 

 traced through the whole range of creation, according to which 

 the higher we ascend in the scale of created beings, the more 

 ample special and complex provisions are made for the mani- 

 festations of a more extended sphere of activity of individual 

 life ; the greater its intensity the more special the apparatus 

 for its manifestations. Thus the nervous system, the most 

 important of all, has reached in man the acme of its develop- 

 ment as a whole, while, as an instance of special endowment, 

 I may mention, that every hair of the beard of a cat is pro- 

 vided with its own separate nerve, having a special purpose to 

 fulfil in facilitating the carrying out of a powerful instinct 

 peculiar to this order of animals. The same relation obtains 

 with regard to other systems of the body ; compare, for in- 

 stance, the beautiful mechanism of the human hand with the 

 corresponding member of the monkey. To what a variety of 

 complicated and intricate operations is it not well adapted in 

 being provided with a number of muscles serving special 

 purposes ? Though the monkey can grasp a stick, he cannot 

 perform the act of pointing, the indicator muscle being absent. 

 What has been stated with regard to sensibility is not less 

 true as regards irritability. If taken in the sense of Haller, 

 as a property of the muscle, it becomes at once identified with 

 muscularity, and in this sense, of course, no one would think 

 of claiming it as an attribute possessed by plants ; yet plants 

 undoubtedly possess irritability, and so do many animals, 

 whichj as is admitted, are devoid of muscularity ; no traces 

 of the fibrillae of muscle exist in the animalcula? and many 

 allied beings, yet nature has provided a substitute, viz., sar- 

 code, which may, for aught ice know, perfectly supply the 

 place and functions assigned to nerves and muscles in the 

 higher animals. But we must go still further, and claim for 

 plants not only sensibility and irritability, but instinct* also. 



* Taken in the sense as apphed to animals, which arbitrarih/ and 

 irresiatihly impels them to the performance of certain actions always 

 directed towards a definite ohject, conformable to their nature, tending to 

 their well-being or propagation, yet ivithout their being conscious thereof. 



