in TARCHANOFF'S EXPERIMENTS 145 



phological diagnosis, a chemico-physiological diag- 

 nosis shall be added, whose importance shall often, if 

 not always, be much greater than that of the former. 



As I have dwelt at some length on the topic, I 

 might be expected now to dismiss it, after having 

 shown that variation is to be found in every part of the 

 organism, even in its deepest and most secluded nooks ; 

 but there arc still some important matters to be dis- 

 cussed. Concerning physiological variability, many 

 experiments might be suggested, and some have 

 been made which show that physiological variations 

 may be experimentally induced. Professor Jean de 

 Tarchanoff, 1 investigating the physiological condition 

 of the brain of new-born animals, has shown that this 

 part of the nervous system does not at birth answer 

 with the normal activity to external stimulations. 

 While Fritsch and Hitzig, afterwards followed by 

 Ferrier and a number of physiologists, established the 

 fact that stimulation of certain parts of the mid-brain 

 is followed by motor reactions in various parts of the 

 body, Tarchanoff has shown that during the first days 

 of life, and especially among the animals which enter 

 upon life with closed eyelids, no motor reaction at all 

 is produced. This is an important feature from the 



1 Sur les Centres Psycho-moteurs des Animaux notiveau-nes et leur 

 Develop f>euient dans differentes Conditions. Rev. Mensuelle de Mede- 

 cine et de Chirurgie, 1878. 



L 



