The origin of zymotic diseases / by F.A. Cooper.

  • Cooper, F.A.
Date:
[1897?]
Catalogue details

Licence: Public Domain Mark

Credit: The origin of zymotic diseases / by F.A. Cooper. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The embryonic evidence can be summed up in the state- ment that certain organs, particularly of the mouth, appear during development within the egg in a form resembling that in the imago or perfect insect, and differing from the same organs in the larva, from which it is inferred the original development was direct to the pel feet insect, and that the larva is a secondary develop- ment since the perfect insect was formed. Here the embryonic evidence is positive fact, capable at any time of verification, but the conclusion drawn is hyj^othesis pure and simple, and is no better than any other hypothesis that will equally well agree with all the facts , for instance, that the organs of the imago are a reversion to a former type, from which the ]3resent larva has grown the true interpretation of the facts, as otlier evidence will show. If these two hypotheses stood alone without other evidence, neither could be used as evidence against any theory that agreed wuth the other, and tbe fact that this other agreed with a theory that explained independent facts—as this larval theory of zymotic disease— would be strong evidence of the truth of the latter, and consequent falsity of the accepted hypothesis—in this case of Fritz Muller’s. ' j Again, that there is nothing in the changed organs of the I mouth, &c., of the larva but wdiat may reasonably be | ascribed to development dependent on the special life of j the larva its environment—can be at once inferred from two following extracts from Lubbock (“Origin, &c., of
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