2b2 



NATURE 



[December 31, 1908 



fret data of ils incidence in Europeans, and hearsay 

 slatenienls of ils absence elsewliere lo guide him, he liule 

 comprehended the futility of the explanations he so lightly 

 advanced, and others of his kind equally lightly refuted. 

 A general feeling of the hopelessness of penetrating lo 

 the truth was abroad, both among the public and the 

 medical profession, who, the limits of surgical aid having 

 been reached, were des[>ondent in the extreme. The 

 universality of this conviction led to the spontaneous and 

 independent formation of " cancer research committees " 

 in different countries at the end of the nineteenth century. 



The whole outlook of the cancer question has been 

 I hanged by the successful application of the comparative 

 biological and experimental methods to its study, and by 

 the restoration of the legitimate relations of observation, 

 speculation, and experimental verification. In this revival 

 the committees formed in different centres have played 

 very unequal shares, according as their proceedings have 

 conformed to the inethods which advance natural know^- 

 ledge. To demon.strate fully the adequate evidence upon 

 which the claim — cautiously advanced in the first and 

 second scientific reports and earlier papers — is based that 

 a new and rational era of investigation has been in- 

 augurated, and to urge continued confidence in the 

 investigation of cancer, are the primarv objects and the 

 main justifications of the third scientific report of the 

 Imperial Cancer Research. The time has not come when 

 practical applications of the additions to' knowledge are to 

 be expected, nor has accident yet yielded any. 



Although the rapid accumulation of new- facts forbids 

 the premature formulation of a generalisation attempting 

 a unification of the mass of new and old knowledge, many 

 results of far-reaching importance have been attained. 

 The work of recent years has made it more certain than 

 it ever was before that cancer contains no virus or other 

 parasite foreign to the living organism. One is often 

 asked if a relative suffering from cancer is dangerous to 

 others, eg,, a grandmother to her grandchild — the chief 

 solace of her old age — or if an historic family mansion 

 should be burnt down because many progenitors inheriting 

 it had died of cancer. During six years many lens of 

 thousands of mice suffering from cancer have been under 

 the most stringent observation. If cancer were con- 

 municable in the sense in which infective diseases are 

 rommunlcabli', animals housed along with those naturally 

 suffering from, or inoculated with, cancer would be the 

 first to suffer. In an experience extending over six years, 

 i.e. almost three times the average length of a mouse's life, 

 exhaustive investig,ition has shown that this risk does not 

 exist. This fact of itself satisfies those handling the 

 animals. They incur still less risk in passing manv hours 

 daily dealing with cancerous animals in a room in whic'i 

 TO, 000 of such mice and rats are usually housed at one 

 time. If such a " cancer house " as never before existed 

 has no dangers to human beings who spend their davs in 

 it, a fortion other persons have no ground for .ipp-- - 

 hension. These results arc of great practical value. They 

 reinforce ooinions often expressed in the past for other 

 reasons. The presence, every day in the year, of some 

 50,000 persons suffering from cancer in England and 

 Wales constitutes no menace to the health of those near 

 and dear to them, nor to the health of the population 

 generally, as w-ould a stnaller number of people suffering 

 from snnll-pox. Notwithstanding the unwise assertions 

 irresponsible enthusiasts will continue to make from time 

 to time, what was a justifiable cause of public alnrm has 

 been removed by experiments on the transference of cancer 

 from one animal to another, and on the housing of large 

 numbers of cancerous with sound animals over a prolonged 

 period. It has been demonstrated completely that artificial 

 transference from animal to animal is due to the impl:mta- 

 lion of living cells. This is a factor which does not come 

 in at all in reference to the frequency of soontnneous 

 cancer in man or animals. In corresponding observations 

 on mice suffering from spontaneous cancer no case of 

 transference has occurred. 



In this respect cancer pre.sents a marked contrast to 

 other diseases, e.g. tuberculosis, equally widelv disse'iiin- 

 ated and common to man and the whole vertebrate phylum, 

 for although no race of mankind is exempt, and cancer 

 extends down the vertebrate scale to marine fish living in 

 NO. 20^4, VOL. 79] 



a statu of nature, there are the most strilving limitations to 

 its communication from one individual to another. There 

 is no connecting link, as it were, between the disease as 

 it presents itself in nearly allied species nor yet even in in- 

 dividuals of the same species. There is nothing which, 

 while foreign to the animal body, is nevertheless common lo 

 cancer wherever it occurs. There is nothing equivalent, 

 e.g., to the characteristics of tuberculous tissues which, no 

 matter what the species of animal, are stamped with unmis- 

 takable common features by the presence of the tubercle 

 bacillus. The properties of the tubercle bacillus obscure 

 all the natural properties of the tissue containing it, and 

 they confer upon such tissue new properties essentially 

 the same in all species of animals. Tubercular tissue has 

 common properties in all animals ; the distinctions of 

 species, and of individual tissues of one and the same 

 species, are submerged in their acquirement of a new 

 property, conferring on them _ the power of conveying 

 the disease to previously healthy tissues, not only from one 

 animal lo another of the same species, but also to others 

 of different species. The tuberculous tissues themselves, 

 however, die when transferred to a new animal ; they do 

 not grow, they merely hand on the cause of the disease. 

 viz. the bacteria, which continue to grow in new soil. 

 How, then, is the pervasion of the animal kingdom b> 

 cancer explicable? It is intelligible because experiaient 

 has proved that cancerous tissues retain, not only the 

 characters of the species of animal, but also those fealurc'- 

 distinguishing the several normal tissues of an individual 

 and because the general conclusion from comparative and 

 experimental investigation is that cancer arises de novo 

 in each individual attacked, by a transforination of health) 

 tissue, one case of cancer having no relation to any other 

 This general conclusion is based upon observations ant' 

 experiments of very varied but confirmatory nature. 



When a piece of cancer-tissue of a mouse is implanted 

 into another mouse, certain of the cells continue to gro\>' 

 in the new animal and others die. The cells which con- 

 tinue lo grow are the cancer cells proper. The othe- 

 cells wiiicli die, formed the scaffolding of supporting con- 

 nective tissues and blood-vessels. The process of trans- 

 ference ran be repeated ad infinitiini, the powers of growth 

 of the cancer cell being inexhaustible ; they set at dcfianc" 

 the laws deleriiiining the specific sizes of the bodies and 

 the organs of vertebrates, and determining the specific 

 duration of the lives of different vertebrates. The cancer 

 cells retain their characters unaltered in the course of 

 artificial propagation, and the connective tissue scaffold- 

 ing, supplied afresli by each successive host, remains 

 identical with that which the cancer cells had in the 

 animal where they originated. This scaffolding is called 

 forth by ihe cancer cells themselves, and is of the nature 

 of a specific reaction on the part of the ordinary con- 

 nective tissues and blood-vessels of the host. The scaffold 

 ing is characteristically different for different tuinours, and 

 as will be stated below, the cancer cell is unable to con- 

 tinue to live and grow without it. The propagation of 

 cancer is only possible in anim:ils of the same species, c..?. 

 ! from mouse to mouse or rat lo rat, but not from mouse 

 10 rat or vice vcrsA. 



Since the limits to transplantation are the same as those 

 which limit the transplantation of normal tissues, e.g. thi 

 grafting of skin, the fads are of themselves evidence tha' 

 cancer tissue contains nothing extraneous to the animal 

 in which it appears. The distinctive differences in the 

 new scaffolding which different tumours even of the same 

 organ, e.g. the mamma, re-acquire after every transplantn 

 tion are inexplicable on the assumption that the lumou- 

 cells contain a common virus endowing them with their 

 peculiar properties. Thorough investigation of questions 

 of metabolism has shown the relations of a tumour to it- 

 host to be merely those of nutrition, similar to those of 

 the foetus in iitero to its mother. More than seventy 

 transplantable tumours of verv varied nature have been 

 studied in the laboratory, and the above facts hold for 

 them all. 



The leatures of growth and of histology exhibited by 

 different spontaneous tumours remain distinctive in the 

 course of continued propagation, and they give weighty 

 indic-'itions of the nature of the changes resnonsible for the 

 acquisition of cancerous properties, since there is neither 



