718 A TEXTBOOK OF PHYSIOLOGY 



After recovering from the operation, the animal snapped at food 

 and licked milk when it was brought right against its mouth. It 

 took no notice of another dog or of a " strong-smelling " cat held in 

 front of its nose. Taste was preserved; meat soaked in quinine Ava- 

 rejected with signs of anger. Tasty morsels, however, were eagerly 

 devoured. After a good meal it curled up and slept like an ordinary 

 dog, but never showed any signs of dreaming. Sleep generally 

 was of shorter duration than normal. It could only be awakened 

 by very loud noises, such as the notes of a fog-horn ; it then moved 

 its ears and made pawing movements at them. The animal could 

 also be awakened by blowing tobacco-smoke into its nose an act 

 which sometimes caused sneezing. A strong light on the eyes some- 

 times caused it to turn the head away, but men and animals 

 were not recognized. The pupils reacted to light normally. 

 Threatening noises had no effect. Co-ordination of muscles was 

 retained, and, when one foot was injured, it could walk on three legs. 

 There was always, however, some muscular weakness, especially of the 

 hind-quarters. The animal never showed any signs of joy or pleasure, 

 invt signs of rage when the cage was touched. It showed no signs of 

 purposive movement, and was always but " a child of the moment." 

 Its tone feeling was due to the preservation of the thalamus. After 

 ligation of all four cerebral arteries, a dog may be in a similar condition 

 for a day or two. and then recover, as a collateral circulation becomes 

 established by way of the superior intercostal, anterior spinal, and 

 basilar arteries. Corresponding to the k " idiot "' stage, the cortical 

 cells are found to have swollen nuclei and loss of Nissl granules. 



In marked contrast is the effect of removal of one cerebral hemi- 

 sphere only. A dog from which the left cerebral hemisphere had been 

 removed fifteen months before appeared quite a " healthy, Avell- 

 behaved animal." When' greeted, it came wagging its tail to be 

 stroked. It would follow anyone, moving quickly by running or 

 even springing He greeted a new-comer with a joyful bark, but 

 snarled at .stranti ;> dogs if he did not like the look of them. He held 

 a bonv with hiri fore-paws, but did not use the right foot so purpose- 

 fully as the left. He could turn round both ways, but preferred to go 

 round to the left. Sensation was diminished over the right side of 

 the body, but was nowhere absent. When irritated, he would at first 

 move away, then yelp, and finally bite. Diminished sensation was 

 well shown by the dog's failure to respond to a jet of air blown by ;i 

 bellows among its hair. When this was done on the left side, the 

 dog turned round to see what was happening, and moved away from 

 the stimulus; when done on the right side in an identical spot, the 

 animal took no notice at all. 'He would also stand in cold water 

 with the right paw, but immediately took the left out. While running 

 and jumping, all obstacles were avoided. Interference of vision was 

 shown by the swinging of a club in the fields of vision. In the right 

 field this caused no response. The left eyeball could be touched with- 

 out evoking a wink. Touching an eyelash immediately evoked a wink. 

 Hearing was somewhat interfered with, but there was apparently no 



