THE WONDERS OF LIFE 



function which is discharged by this section. Thus 

 disease of the speech-centre, in the third frontal convolu- 

 tion, destroys the power of speech; the destruction of 

 the visual region (in the occipital convolutions) does 

 away with tjie power of sight; the lesion of the temporal 

 convolutions destroys hearing. Nature herself here con- 

 ducts delicate experiments which the physiologist could 

 only accomplish very imperfectly or not at all. And al- 

 though we have in this way only succeeded as yet in 

 showing the functional dependence of a certain part of the 

 mental functions on the respective parts of the cerebrum, 

 no unprejudiced physician doubts to-day that it is 

 equally true of the other parts. Each special mental 

 activity is determined by the normal constitution of the 

 relevant part of the brain, a section of the phronema. 

 Very striking examples of this are afforded in the case 

 of idiots and microcephaU, the unfortunate beings whose 

 cerebrum is more or less stunted, and who have accord- 

 ingly to remain throughout life at a low stage of mental 

 capacity. These poor creatures would be in a very 

 pitiable condition if they had a clear consciousness of it, 

 but that is not the case. They are like vertebrates 

 from which the cerebrum has been partly or wholly 

 removed in the laboratory. These may live for a long 

 time, be artificially fed, and execute automatic or 

 reflex (and in part purposive) motions, without our 

 perceiving a trace of consciousness, reason, or other 

 mental function in them. 



The embryology of the child-soul has been known in a 

 general way for thousands of years, and has been an 

 object of keen interest to all observant parents and 

 teachers; but it was not until about twenty years ago 

 that a strictly scientific study was made of this remark- 

 able and important phenomenon. In 1884 KuSsmaul 

 published his Untersuchungen iiber das Seelenleben des 

 neugeborenen Menschen, and in 1882 W. Preyer pub- 



