Individual through the Nervous System. 97 



in number, not only to the ideas expressed by the words of a 

 language, but also to those which may be expressed by any 

 combinations of such words. Hence, we find an abundant source 

 of excitants, whose duty it is to furnish a considerable part of 

 the operations and development of the nervous system. 



But what is the ideogenic docrine held by physiologists ? 

 What the origin of the ideas of which society is in possession ? 

 It is admitted on all hands that these ideas are not only ori- 

 ginated but disposed of, in the several operations of man's 

 sensibility, understanding, and will. This is a matter of uni- 

 versal observation and belief. Between collective life and that 

 of the individual, there exists a series of relations which the 

 neurologist is bound to study. The mediation of the signs of 

 language in the cerebral functions, as well as the moral and 

 intellectual acts of man, are embraced in this study, for these 

 are the result of an affinity, pre-established between the psycho- 

 cerebral functions and the signs of language, and these signs are 

 the appropriate figures of the mind, by which it acts upon the 

 brain in order easily to discharge its function in the complicated 

 acts of the understanding, and they not only furnish to the 

 ideas a means of transmission and preservation, but, in addition, 

 furnish to the psycho-cerebral operations an indispensable aid. 

 Now, the psycho-cerebral organs, in their marvellous func- 

 tions, demand in some way the mediation of these signs, just 

 as the respiratory organs, in changing the composition of the 

 blood, demand the mediation of air ; just as the digestive 

 organs in the process of nutrition demand the mediation of 

 proper food ; or just as the sensorial organs demand the 

 mediation of colours, sounds, temperature, and resistance. 

 Without speech, which really crystallises the floating vapours of 

 ideas, and thus concentrates into form the acts of the mind, 

 man might preserve a confused image of an isolated act, a vague 

 notion or a hazy conception, but he would lack a form in which 

 to recall it, an embodiment upon which the mind could rest. It 

 would thus be impossible for him to acquire those ideas which 

 concern the existence of the related deductions in his sensorial 



