FUNCTIONS OF THE BRAIN-STEM AS A WHOLE 



625 



more exact observations on their behavior, as the animals in these experiments 

 were not observed for more than twelve hours after the operation. 



It appears from Christiani's observations that this regulation is the work of 

 the 'tweenbrain, for in rabbits deprived of this part, or in which it was exten- 

 sively injured, the coordination necessary for locomotion and for maintaining 

 the equilibrium in sitting and standing was entirely lost. 



Much more significant than these observations are those of Goltz on a de- 

 cerebrated dog which survived the operation for a long time. In this dog, 

 whose history we shall now relate, not only was practically all the cerebrum 

 destroyed, but the 'tweenbrain and to a large extent the corpora quadrigemina on 

 the left side as well. The functions carried out 

 by this dog were therefore probably less extensive 

 than would be possible if the cerebrum only were 

 extirpated. Since this experiment is of the ut- 

 most importance for a proper conception of the 

 functions of the central nervous system, we shall 

 report it somewhat extensively. 



The left hemisphere of this dog was removed 

 in two operations on the 27th of June and the 

 23d of November, 1889, the entire right hemi- 

 sphere was removed in one operation on the 17th 

 of June, 1890. The dog lived until December 31, 

 1891, when he was killed by bleeding, and was 

 therefore under observation for a year and a half 

 after the last operation. Fig. 281 is a picture of 

 the brain as it appeared at autopsy. 



On the third day after the last operation 

 (June 20, 1890) the animal walked about the 

 room without falling. From this time on his 

 strength increased so rapidly that on the 22d of 

 July he easily climbed up an inclined plane of 

 twenty degrees. The ability to perform crude 

 muscular movements was therefore perfect. 



After some months considerable disturbance 

 in nutrition made its appearance, the hind parts 

 becoming more and more emaciated. By feeding 

 the animal heavily this progressive emaciation 

 was finally overcome, but the certainty of the 

 dog's movements, which was so plain a feature 

 for a few weeks after the operation, did not re- 

 turn. In spite of this until a few days before his 

 death he was able to raise himself on his hind legs 

 and to place his paws on the grating of his cage. 



According to Goltz himself the cause of this 

 emaciation lay partly in the fact that the animal 



continually moved about in his cage and that he never rested nor slept so long 

 as a normal animal. It is probable also that it was due to imperfect heat regu- 

 lation, since the heat loss was greater than normal. At any rate it is stated 

 that the skin was noticeably warm. Otherwise, judging by nothing more than 

 the fact that the animal lived so long, the heat regulation must have been fairly 

 good. When the dog slept, he curled up as normal dogs do; in a warm room he 

 panted and stretched out his tongue; and in a cold room he shivered, 



FIG. 281. The remainder of the 

 brain of Goltz's dog, after re- 

 moval of the cerebral hemi- 

 spheres. The medulla, pons, 

 cerebellum and the roots of 

 all the cranial nerves con- 

 nected with the medulla and 

 pons were perfectly normal. 

 The corpora quadrigemina 

 were somewhat degenerated. 

 All that was left of the cere- 

 bral cortex was a small portion 

 of the temporal lobe on each 

 side. 



