CELLULAR RESISTANCE 171 



chronic inflammatory reaction in which lymphocytes appear in con- 

 siderable numbers. J. B. Murphy and his collaborators have put to 

 the test of experiment the hypothesis that lymphocytes are of import- 

 ance in resistance to cancer. By the use of the X-ray they were able 

 to destroy practically all the lymphoid tissue of the body of animals and 

 found in these animals a decreased resistance to transplanted cancer. 

 Immunity already established to cancer was also destroyed by this 

 procedure. Similarly there was a lowered resistance to tuberculosis 

 and to anterior poliomyelitis. In tuberculosis the lymphocyte constitutes 

 a large element in the inflammatory reaction, and this is true also in the 

 later stages of acute anterior poliomyelitis. Although small doses of 

 X-ray may stimulate lymphocyte production, Murphy and his asso- 

 ciates found that dry heat produces a more durable increase in the 

 circulating lymphocytes. By increasing the lymphocytes in this fashion 

 they demonstrated " the establishment of a high degree of immunity 

 to certain transplantable cancers in mice," regardless of whether these 

 cancers naturally showed a high or low percentage of successful inocula- 

 tion. The same was found to be true in regard to the implantation of 

 grafts from spontaneous cancers into the animals from which the 

 grafts were removed. This subject has also been studied by F. C. 

 Wood and associates in the Crocker Laboratory. They found that mice 

 with lymphatic leucemia show no demonstrable immunity to tumors. 

 They found that reduction of the total leucocyte count by means of 

 X-ray or radium produces no increase in the successful transplanta- 

 tion of normal tissues. They found further that successful transplan- 

 tation of the guinea-pig fibrosarcoma is not influenced by the use of 

 X-ray. They selected an immune strain of rats, exposed them to X-ray 

 and found no change in susceptibility to transplantable tumors. They 

 found that the use of X-ray on rats in which a highly virulent tumor had 

 been implanted did not prolong the life of the tumor. Wood states 

 that " it is, therefore, evident that the lymphocyte is in no way corre- 

 lated with cancer immunity." Sittenfield also found that artificial 

 lymphocytosis has no effect whatever on tumor growth. It is of further 

 interest that in human cancer the lymphocytes collect about the slowly- 

 growing rather than the rapidly-growing tumors and that the metastases 

 are frequent in the lymph-nodes. The later experiments of Murphy 

 on the lymphocytosis induced by heat have not received as yet extensive 

 examination ; therefore, the question remains open. Murphy's experi- 

 ments are so well conducted that it is difficult to be assured that the 

 lymphocytes play no part. The work of Wood carried out on a large 

 number of animals is of especial significance and would indicate that 

 the lymphocyte plays no such important part in resistance to cancer as 

 Murphy's work appears to indicate. 



Platelets. In 1901 Levaditi noticed that following the injection of 

 cholera vibrios they were often found clumped around small masses 

 of platelets. The phenomenon was called thigmotropism. Govaerts 

 subsequently demonstrated that the clumping is influenced by the action 

 of opsonins. LeFevre found that anti-bacterial immunization increases 



