The graft theory of disease : being an application of Mr. Darwin's hypothesis of pangenesis to the explanation of the phenomena of the zymotic diseases / by James Ross.

Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: The graft theory of disease : being an application of Mr. Darwin's hypothesis of pangenesis to the explanation of the phenomena of the zymotic diseases / by James Ross. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    <38 production of new individuals may be carried for- ward to the explanation of contagious diseases, it is in the highest degree probable that a particle de- tached from a healthy body would produce no result by coming into contact with another healthy body ; and that it is only after the detached particle has been previously modified and individualised by what we call a diseased process, that its collision with a healthy body would produce any marked result. It has already been noticed that the contagium particles are detached from the body because the supply of nourishment fails them ; hence it may be inferred that they are on the verge of reaching that state of molecular equilibrium which constitutes death. And the same may be said with regard to the reproductive particles. “ The next general fact,” says Mr. Herbert Spencer, “to be noted is, that these cells whose union constitutes the essential act of gamogenesis, are cells in which the develop- mental changes have come to a close; cells which, however favourably circumstanced in respect of nu- trition, are incapable of further evolution. Though they are not, as many cells are, unfitted for growth and metamorphosis by being highly specialized, yet they have lost the power of growth and metamor- phosis. They have severally reached a state of equilibrium.” * After noticing that when the sperm- cells and germ-cells which are not brought into contact disappear, Mr. Spencer adds: “ But the