June 23, 1916] 



SCIENCE 



881 



many. Whether infected or only degen- 

 erate, these cells retain their hereditary 

 tendencies, that is, liver cells to reproduce 

 liver; brain cells, brain; connective tissue 

 cells, connective tissue; and so on; but all 

 of them while deriving nourishment from 

 the body have become more or less emanci- 

 pated from body control and exercise their 

 freedom by an unlimited and hasty multi- 

 plication very destructive to the other 

 tissues of the body. They reproduce their 

 kind first in the primary tumor and later 

 in secondary tumors. I can make this 

 plainer perhaps by another illustration. 

 Following tuberculosis of the lungs there 

 sometimes occurs blood-infection and a gen- 

 eralized tuberculosis of every organ in the 

 body, but in such cases the nodules wher- 

 ever they arise are due to local bacterial 

 irritation, and are always built up out of 

 local tissues, liver tissue in the liver, spleen 

 tissue in the spleen, and so on. In cancer, 

 on the contrary, it is the cancer cell which 

 migrates with all its hereditary tendencies 

 and tite secondary tumor, therefore, repro- 

 duces more or less perfectly (or imper- 

 fectly) the hereditary cell complex of the 

 primary tumor, so that the trained pathol- 

 ogist after studying sections of a cancer 

 can usually (but not always) decide 

 whether it is primary in the organ under 

 examination, or secondary, and if second- 

 ary, then in what other organ the primary 

 tumor is to be sought. For example, if a 

 primary cancer occurs in the liver and 

 there are metastases to the lungs the lung 

 tumors will contain liver cells; so if a pri- 

 mary cancer occurs in the stomach and 

 there is metastasis to the liver, the liver 

 tumor will not be formed out of liver cells 

 but out of stomach cells. It is a very stri- 

 king thing to see under the microscope, 

 particularly in a well-stained section, a nest 

 of malignant glandular stomach cells in 

 the midst of a piece of liver. I do not know 



that it has been actually proved but un- 

 doubtedly such a liver tumor must have the 

 power of secreting pepsin or at least of 

 mucin, just as we know that metastases 

 from a primary liver tumor into other 

 organs may retain the power of secreting 

 bile. 



I have now come to another way in which 

 these plant tumors resemble cancer in man 

 and the lower animals, viz., in the striking 

 fact that as in animals the secondary 

 tumors reproduce the structure of the pri- 

 mary tumor. Thus, when a primary tumor 

 is induced on a daisy stem by inoculation, 

 deep-seated secondary tumors, developed 

 from parenchymatic tumor-strands, often 

 arise in the leaves and these tumors convert 

 the unilateral leaf or some portion of it 

 into the concentric closed structure of a 

 stem. (Slides shown.) 



Having now reviewed my older discov- 

 eries," I come to details of more recent ones 

 also bearing directly, I believe, on the 

 etiology of cancer. 



I have referred to the rapid growth and 

 early decay of cancers in men and to the 

 common occurrence of atrophy and cachexia 

 in connection with such tumors. Similar 

 phenomena occur in the plant. I show you 

 three slides from photographs of galled 

 sugar beets. They were grown in different 

 years (1907, 1913 and 1916) but each 

 showed the same thing, viz., sound control 

 plants and dwarfed, sickly (yellow) and 

 dying inoculated plants. Each inoculated 

 plant bore a tumor larger than itself and 

 the time from inoculation to date of the 

 photograph varied from 2i/^ to 4% months. 

 This year I have obtained the same results 

 on ornamental (white flowered) tobacco. 

 At the end of five months all of these inocu- 

 lated tobaccoes are dead or dying from 

 large tumors of the crown, whereas the con- 

 trol plants are healthy, many times larger 



6 See this journal, N. S., Vol. XXXV., p. 161. 



