336 NERVOUS SYSTEM. 



factorily analyzed by Yulpian. 1 Goltz argues, from experi- 

 ments on frogs and the movements executed after extirpation 

 of 'the brain, that these animals make intelligent muscular 

 efforts when deprived of the hemispheres ; and the phenom- 

 ena observed after this mutilation are indeed very curious. 

 As was shown by Yulpian, in his own experiments, frogs and 

 fishes thrown into water will swim about and the frogs will 

 even succeed in getting out of the water, but then they im- 

 mediately relapse into a torpid condition. We do not con- 

 ceive that these facts are in opposition to the statement just 

 made with regard to the absence of spontaneous volition in 

 birds and the mammalia, particularly in view of the slight 

 importance of the functions of the cerebrum as compared with 

 the spinal cord in the lower orders of vertebrate animals. 

 The views lately advanced by Yoit are based upon an iso- 

 lated experiment upon a pigeon that was kept alive for five 

 months after the cerebral lobes had been, as stated by Yoit, 

 completely removed. At first the pigeon presented the phe- 

 nomena usually observed after this operation ; but it gradu- 

 ally recovered, until finally it seemed entirely normal, with 

 the single exception that it never would eat, all food being 

 introduced forcibly. Five months after the operation, the 

 pigeon was killed and the encephalic cavity was found filled 

 with a white substance containing dark-bordered nerve-fibres 

 and 'nerve-cells. Yoit never before observed any thing like 

 regeneration of the nervous substance or so complete a res- 

 toration of the cerebral functions ; and he regarded this as 

 an instance of anatomical and physiological regeneration of 

 the hemispheres. The objections to accepting this observa- 

 tion with the physiological conclusions presented by Yoit 

 are, that it is not only possible but probable, that the hemi- 

 spheres were not entirely removed, and that the posterior 

 portion of the encephalon had advanced to occupy in part 

 the space originally filled by the extirpated mass. 2 "While 



1 Archives de physiologic, Paris, 1869, tome ii., p. 301. 



5 GOLTZ, Contributions d Petude des fonctions du cerveau de la grenouille ; 



