ALLEGED MICROBIC ORIGIN OF TUMORS. 253 



lung. Foil in and Lebert asserted that they had been similarly 

 successful in transmitting the disease from man to animals. From 

 sixty to seventy grammes of finely triturated cancer juice taken 

 from a cancer of the breast were mixed with distilled water and 

 injected into the jugular vein of a dog. The animal died two 

 weeks after the inoculation, when a few firm elastic nodules, the 

 size of a pea, were found in the walls of the heart, and numerous 

 nodules, the size of the head of a pin, throughout the liver. Bill- 

 roth, Maas, Doutrelepont, Alberts, Senger, and others obtained 

 only negative results. Doutrelepont made inoculations from ani- 

 mal to animal with no better effect. In cases of cancer of the peri- 

 toneum it has been known for a long time that local dissemination 

 takes place by detached minute particles leaving the primary matrix 

 and becoming implanted upon the peritoneal surface forming new 

 independent centres of growth. Implantation of cancer cells upon 

 the surface of wounds made for the removal of a carcinoma has been 

 recognized as one of the ways in which the disease returns. Trau- 

 matic dissemination of carcinoma is recognized by Billroth, \Val- 

 deyer, Bergmanu, Reineke, and others. 



At a meeting of the Medical Society in Zurich, Hauau (British 

 Med. Journal, October 19, 1889) claimed that he had succeeded in 

 inoculating carcinoma from rat to rat. On November 28, 1888, 

 he excised two pieces of a carcinomatous lymphatic gland from a 

 female rat with malignant disease of the vulva, and transplanted 

 these into the right half of the scrotum in two male rats. One of 

 the latter died on January 14, 1889. The necropsy revealed a 

 generalized carcinosis of the peritoneum and omentum. In the 

 other, which was killed on January 25th, there were found two 

 typical cancroid nodules, the size of a pea, on the gubernaculum 

 testis and the cauda of the epididymis. The transplanted malig- 

 nant growths proved to have precisely the same structure as those 

 which had spontaneously originated in the first animal. According 

 to Hanau's theory, the carciuomatous infection should be attributed 

 to the agency of young epithelial cells and not to any pathogenic 

 microbe. This theory would explain satisfactorily the few instances 

 where transplantation of malignant grafts yielded a positive result. 



During the last eight years I have made numerous implantation 

 experiments of carcinoma and sarcoma tissue in dogs, cats, rabbits, 

 and guinea-pigs, and have invariably observed that the graft failed 

 to increase in size. The apparent increase in size a few days after 

 implantation was due to the formation of a wall of granulation 

 tissue around the graft in which it becomes embedded. The ex- 

 periments were made by taking a graft the size of a pea from the 

 periphery of the malignant tumor and inserting it under the skin, 

 usually in the inguinal region. After three to four weeks without 



