PROTOPLASM. 2 I 



anything else a minute mass of jelly, and which, appear 

 to be made up almost solely of this albuminous protoplasm, 

 there are movements in correspondence with the needs of 

 the organism, whether with respect to seizing food 

 or any other purpose, which are unaccountable accord- 

 ing to any known physical laws, and can only be called 

 vital. In many, too, there is a kind of molecular cur- 

 rent, exactly resembling that which is seen in a vegetable 

 ceU. 



In the higher animals, phenomena such as these are so 

 subordinate to the more complex manifestations of life that 

 they are apt to be overlooked ; but they exist nevertheless. 

 The mere nutrition of each part of the body in man or in 

 the higher animals, is performed after a fashion which is 

 strictly analogous to that which holds good in the case of 

 a vegetable cell, or a rhizopod ; or, in other words, the 

 life of each anatomical element in a complex structure, 

 like the human body, resembles very closely the life of 

 what in the lowest organisms constitutes the whole being. 

 For example, the thin scaly covering or epidermis, which 

 forms the outer part of a man's skin, is made up of minute 

 cells, which, when living, are composed in part of pro- 

 toplasm, and which are continually wearing away and 

 being replaced by new similar elements from beneath ; 

 and this process of quick waste and repair could only take 

 place under the very complex conditions of nutrition which 

 exist in man. One working part of the organism of an 

 animal is so inextricably interwoven with that of another, 

 that any want or defect in one, is soon or immediately felt 

 by the whole ; and the epidermis, which only subserves a 

 mechanical function, w T ould be altered very soon by any 

 defect in the more essential parts concerned in circulation, 

 respiration, &c. But if we take simply the life-history 

 of one of the small cells which constitute the epidermis, 

 we find that it absorbs nourishment from the parts around, 

 grows, and developes in a manner analogous to that which 



