The constancy and variability of tumour-cells during propogation / by E.F. Bashford.

  • Bashford, E. F. (Ernest Francis), 1873-
Date:
1914
Catalogue details

Licence: In copyright

Credit: The constancy and variability of tumour-cells during propogation / by E.F. Bashford. Source: Wellcome Collection.

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    than those to which they belonged, and that the resistance in the two cases was of the same nature. These facts made it necessary to investigate whether the acquisition of progressive growth was due to this resistance being overcome or to loss of power to induce resistance. This problem has been solved partly by re-inoculating mice and rats already bearing tumours exhibiting the different features of growth described above, and partly by studying the production of active resistance in a variety of circumstances. Tumour strains which only exhibit transitory growth in normal animals present exactly the same features in this respect as do normal tissues 1 when inoculated subcutaneously, and both agree in producing resistance to the growth of tumour or normal tissue inoculated subse¬ quently. The inoculation of an animal's own tissues (and as a special case, of a spontaneous tumour into the animal bearing it) produces no immunity reaction against tumour grafting. Tumour-cells or normal cells inoculated into new animals of the same species produce resistance, however, both to tumour grafting and to their own growth, and it has been shown that the transitory growth resulting in such experiments is due to inhibition of growth by this actively developed resistance becoming effective concomi¬ tantly with the establishment of the tumour. The progressive growth and dissemination of spontaneous tumours is undoubtedly favoured by the absence of the immune reaction, and experiments have shown that in the case of transplanted tumours, when progressive growth occurs in strains where it is the exception, the immune reaction is weak or absent. When a transplantable tumour strain alters the character, of its growth in normal animals in the direction of becoming progressive, it is found that the concomitant immunizing process has diminished in intensity, and as the normal animals cannot be made responsible for the difference, it has been concluded that the tumour-parenchyma has lost the power of calling forth the reaction. In this way tumours which formerly behaved as do normal tissues on transplantation acquire the manner of growth characteristic of spontaneous tumours in the animals in which they have taken origin. Such tumours have lost the power to induce resistance to their own growth, and so simple and self-evident as the fact now seems, it required very painstaking and careful investigations to demonstrate it. The assumptions involved in the other explanations are not only superfluous but contrary to the facts. 1 There is this difference, however, in the two cases, viz. that although normal tissue cannot yet be grown in an indefinite succession of hosts, these tumours can, if the transplantation is carried out sufficiently early. Ill G 2