240 REPORTS ON INVESTIGATIONS AND PROJECTS. 



garding the association functions of the cerebrum, which was formulated by 

 me largely as the result of the experimental work performed in conjunction 

 with Grant No. 80. The view expressed in that article is briefly that the 

 frontal lobes are concerned with the motor part of the associations, while the 

 posterior area or areas are concerned with the sensory or perceptive parts of 

 the association. This view is in line with the facts which have been gathered 

 by clinicians, and it helps us to understand certain facts regarding cerebral 

 localization in man which have hitherto not been explained or understood. 



(3) The principal work finished during the year was an inquiry into some 

 of the functions of the occipital lobes. A brief account of this work is pub- 

 lished in the American Journal of Physiology, vol. 28, pp. 308-317. The full 

 account of these experiments is now in press and is being published as a 

 monograph supplement to the Psychological Review. 



The conclusions from all the experiments are as follows : Extirpation of 

 the lateral parts of the occipital lobes does not interfere with color discrimi- 

 nation. Extirpation of the lateral parts of the so-called visual cortex in the 

 monkey does not produce disturbances of a true visual character. The de- 

 struction of the lateral parts of the occipital cortex is followed by disturb- 

 ances in coordination of movements, which are based upon the sensations 

 from the eye and its appendages. The disturbances in coordination are not 

 due to a lack or a loss of the true visual element, but to a lack or loss of the 

 afferent motor elements, viz, those from the intrinsic and from the extrinsic 

 eye-muscles. One animal in which the cortex surrounding the calcarine 

 fissure was destroyed showed a true visual disturbance corresponding with 

 those in man. 



ZOOLOGY. 



Castle, W. E., Harvard University, Cambridge, Massachusetts. Grant No. 

 685. Continuation of experimental study of heredity in small mammals. 

 (For previous reports see Year Books Nos. 3-9.) $1,000 



During the past year substantial progress has been made on the several 

 investigations outlined in my last report. 



Dr. John C. Phillips and the grantee have continued their studies on 

 ovarian transplantation. Out of a large number of operations performed on 

 guinea-pigs, two have proved entirely successful (in addition to the one re- 

 ported last year), the grafted animal having in both cases produced young 

 possessing color characters clearly derived from the transplanted tissue and 

 not possessed by either ostensible parent. We have been able to find not the 

 slightest evidence that the characters determined by the transplanted tissue 

 had been influenced by the foreign body within which development occurred. 

 This investigation is being continued. Its result to date affords the strongest 

 existing experimental evidence in support of Weismann's postulate that body 

 and germ-cells are distinct, and that characters which are inherited must have 

 their basis in the germ-cells, characters which the parents may acquire during 

 their lifetime not being transferred to their offspring. Publication No. 144 

 is based on this investigation. 



