8 A. C. IVY 



ency for the quick movements to occur on deviation is generally 

 the case, but in some dogs the quick movement does bring the eye 

 back to the primary position. 



Complete hemi-decerebration and extensive injury to the thal- 

 amus do not abolish the quick component of nystagmus. This 

 statement is based upon observations made on eight dogs that 

 lived from two weeks to eight months following the operation. 

 In some of these animals the lesion was produced in one opera- 

 tion, in others in two operations. Thirteen animals were oper- 

 ated in order to get this group of eight. Five of these animals 

 died in from one to five days showing various symptoms, as con- 

 tinued running movements, howling and crying, rapid respira- 

 tion, vomiting, subnormal temperature, deep depression and 

 coma. These five animals did not show the quick component 

 at any time following the operation. Three of them showed 

 deviation, the other two no eye movements (marked deviation 

 down and out was present) at all on rotation. In one animal the 

 left third nerve was torn from the brain stem. Four of the eight 

 animals kept alive had to be fed and watered daily by artificial 

 methods, as they would neither eat nor drink voluntarily.' 2 All 

 of these animals died of nutritional disturbance/' The other 

 four dogs ate and drank voluntarily in four to ten days after the 

 operation. The lesions were verified by autopsy and brain rem- 

 nants preserved for later anatomical study. 



In two animals with complete hemi-decerebration and lesion 

 to the lateral portion of the thalamus, the remaining motor cor- 

 tex including the eye-motor area and basal portion of the tem- 

 poral lobe was extirpated. Both of these animals showed an 

 increase in the postrotatory nystagmus when rotated to the side 

 opposite the fresh lesion. This latter operation was (lone six 



One w:is nourished via gastrostomy. 

 ; Two df these animals during the Last week of their lives, when t heir tempera- 

 ture was subnormal, passed in the stools particles of undigested food particles 



of i ii whose Bubstance was not even discolored and milk no further changed 



than coagulated. These t wo animals ami three others dying from extensive thal- 

 amus lesions passed liquid red-painl colored stools, which gave positive tests for 

 Mood. Autopsy of the gastro-intestinal trad revealed petechial hemorrhages 

 and hyperemia of i he gastric mucosa, the rest of the intestinal tract being norma I 



