Organic dependence and disease : their origin and significance / by John M. Clarke.

  • Clarke, John Mason, 1857-1925.
Date:
1921
Catalogue details

Licence: In copyright

Credit: Organic dependence and disease : their origin and significance / by John M. Clarke. Source: Wellcome Collection.

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    the existence and earliest appearances among these ele- mentary expressions of life, of conditions which show an actual mutual dependence of creatures one upon another; that is to say, ol the conditions commonly known variously as symbiosis, mutualism and parasitism. Such evidences are not easy to acquire among primitive forms of life as preserved in the rocks of the earth’s historic record, but persistent and long-continued search with the aid of a va- riety of special procedures adapted to the extraction of the peculiar character of the material employed, enlarged by the inspection of many great museum collections and joined with the help of generous colleagues and the special sup- port of the National Academy of Sciences, has resulted in even so much light on these significant paleopathologic problems as is here set forth. The writer desires to present his facts without embar- rassing detail and his conclusions without bias. In his own justification for both he may urge a long acquaintance with nature’s modes in the preservation of such materials in the fossil state and reasonable familiarity, based upon com- parative morphology, with the forms of life that go to make up the earlier faunas and floras of the earth. It will be observed, and special emphasis is put on this, that these chapters deal with the lower forms of life, the invertebrates among animals and cryptogams among the plants. The actual outstanding evidences of pathological and traumatic lesions among extinct animals of the verte- brate type are not comprehended within this discussion as such phenomena are registered only among faunas of the earth too late and too specialized for our consideration. Sucli lesions have been noted by several students of verte- brate paleontology and most interestingly brought together by Dr. Roy L. Moodie, whose investigations into the history of such registered conditions and of the possible effect of disease in the extermination of races of the higher animals through the later ages of the earth are very suggestive to