454 First European Journey 



become an instructor in pathology at the University of Michigan. 

 By 1912 he was an associate member of the research personnel 

 of the Rockefeller Institute for Medical Research. After Smith 

 had heard his address at the American Association for Cancer 

 Research, he sent Rous a letter of congratulations: 



I found your paper of tremendous interest and wish to congratulate you 

 on the beautiful results you are obtaining. Whatever people may have said 

 in the past about the possibility of some living cells of the chicken sarcoma 

 passing through the filter or escaping into the fluid which has been centri- 

 fuged, there can be no dodging the fact that the tumor tissue dried for six 

 months is as dead as a door nail.^^ 



To Smith, Rous had not only shown that " a chicken sarcoma 

 is inoculable in the absence of living chicken cells, i. e., with fluid 

 freed from the ground sarcoma by centrifuging, and also by filtra- 

 tion through moderately coarse Berkefeld bougies," but further 

 that " tumor material dried for six months is still infectious." ^° 



Smith recapitulated in his address of 1912 the evidence bearing 

 out his resemblance theory of crown galls and malignant animal 

 tumors. In crown gall were to be found: 



the cell itself a disturbing force, i. e., an enormous multiplication of cer- 

 tain cells of the body without reference to physiological needs and in 

 opposition to the best interests of the organism; a non-capsulate tumor, 

 with absence of abscess cavities and of plainly visible parasites ; peripheral 

 growth and a well-developed stroma consisting of vessels and fibers ; from 

 this primary tumor the development of strands of tumor tissue upon which 

 secondary tumors develop; in the secondary tumors a strong tendency to 

 take on the structure of the organ in which the primary tumor has 

 developed ; frequent if not necessary origin of the primary tumor in bruises, 

 wounds, or irritated places; complete recovery if all the tumor tissue is 

 extirpated, failure if it is not; in some cases spontaneous recovery. The 

 chief difference so far made out is that in case of cancer cells we know 

 nothing whatever as to the cause of the abnormal growth, whereas in case 

 of these overgrowths on plants we have definitely proved them to be due 

 to the presence of an intracellular schizomycete which we have many times 



^^ Written May 16, 1912, after the cancer research association's Philadelphia 

 meeting. University of Pennsylvania Medical School. Zeitschr. fur Krebsforschung 

 12: 430 ff., 1912. Rous, et al's paper, 430-431; Smith's paper, 435-436. 



*" The structure and development of crown gall, op. cit., 11, introduction. A 

 decade later, Smith again reviewed the work of Rous and his co-workers on Filter- 

 able virus chicken sarcomas. For this purpose, he read twenty-five of his papers. 

 See, Twentieth century advances in cancer research, by Smith, Jour. Radiology 4(9), 

 pt. Ill: 301-303, Sept. 1923. 



