GENERAL USES OF THE CEREBRUM 587 



but had lost the power of perception ; and that they could execute 

 voluntary movements when an irritation was applied to any part, but 

 had lost the power of making such movements in obedience to a spon- 

 taneous effort of the will. One of the most remarkable phenomena 

 observed was entire loss of memory and of the power of connecting 

 ideas. The voluntary muscular system was enfeebled but not paralyzed. 

 Removal of one hemisphere produced, in the higher classes of animals 

 experimented on, enfeeblement of the muscles of the opposite side, 

 but the intellectual faculties were in part or entirely retained. 



The observations of Flourens have been repeated by many physi- 

 ologists, and in the main confirmed, except as regards the special 

 senses. Bouillaud (1826) made a large number of observations on 

 pigeons, fowls, rabbits and other animals, in which, after removal of the 

 hemispheres, he noted the persistence of the senses of sight and hear- 

 ing. Longet finally demonstrated the fact that both sight and hearing 

 are retained after extirpation of the hemispheres, even more clearly 

 than Bouillaud, by the following experiments : he removed the hemi- 

 spheres from a pigeon, the animal surviving the operation eighteen 

 days. When this animal was placed in a dark room and a light was 

 suddenly brought near the eyes, the iris contracted and the animal 

 winked ; " but it was remarkable, that when a lighted candle was moved 

 in a circle, and at a sufficient distance, so that there should be no sensa- 

 tion of heat, the pigeon executed an analogous movement of the head." 

 An examination after death showed that the removal of the cerebrum 

 had been complete. An animal deprived of the hemispheres also opened 

 the eyes at the report of a pistol and gave other evidence that the sense 

 of hearing was retained. 



In regard to the senses of smell and .taste, it is more difficult to 

 determine their presence than to ascertain that the senses of sight and 

 hearing are retained. It is probable, however, that the sense of smell 

 is not abolished, if the hemispheres are carefully removed, leaving the 

 olfactory ganglia intact ; and there is no direct evidence that extirpation 

 of the cerebrum affects the sense of taste ; indeed, in young cats and 

 dogs, Longet noted evidences of a disagreeable impression following , 

 the introduction of a concentrated solution of colocynth into the mostly 

 as distinctly as in the same animals under normal conditions. 



Comparative Development of the Cerebrum in the Lower Animak excep- 

 is necessary only to refer briefly to the development of the cenedemann, 

 the lower animals as compared with the human subject, to rain of an 

 connection of the hemispheres with intelligence. In man the/eighed ten 

 presents a large preponderance in weight over other portiserved, also, 

 encephalon ; but in some of the lower animals the cerebrui? size in idiots 



