Functional Changes in the Brain of the Dog After Reduction of the Cerebral Blood Supply

As was mentioned in paper I of this series,1acute anemia resulting from complete or partial restriction of the cerebral circulation produces temporary or permanent disturbances of higher nervous activity. Loss of intelligence after ligation or temporary compression of the main arteries supplying the brain was observed in different animals (dogs, cats, monkeys and others) by Cooper2(1836), Hill3(1900), Pike, Guthrie and Stewart4(1906), Crile and Dolley5(1908), Gildea and Cobb6(1930) and others. Usually these disturbances were temporary and were noted in the first hours or days of the anemic condition. When the animals were observed longer, most of the authors believed that they recovered completely. It is difficult, however, to judge of the full restoration of the mental processes in animals. Under laboratory conditions these animals manifest all the functions normal to the ordinary animal, although the finest processes of higher