Experimental embryology / by Thomas Hunt Morgan.

  • Morgan, Thomas Hunt, 1866-1945.
Date:
1927
Catalogue details

Licence: In copyright

Credit: Experimental embryology / by Thomas Hunt Morgan. Source: Wellcome Collection.

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    disparage any such attempt. It is true that, since the study of embryology has been largely in the hands of morphologists, the problem of the changes in form through which the embryo passes will seem to them to be the central theme of embryology. On the other hand, physiologists who have studied development have not been enamored of this problem, but have ignored it, either because, I suppose, they were not interested in it, or did not realize its significance, or else because they supposed that the study of living matter has not reached a point where such ques- tions can be profitably discussed. Even if the diagnosis of the morphologist should prove to be nearer the mark, enough work has been done to show that before we can hope to study experi- mentally the changes in form of “the embryo as a whole,” we must first undertake to work out the many kinds of changes that are involved in each separate change in form in order to synthesize these under one or more general headings. It seems, then, more worth while to drop the old fruitless discussions of the meaning of development, and turn to the many problems that have already presented themselves at almost every stage of the process. The application of the experimental method to problems in development is itself an interesting problem. In physics and chemistry the experimental method has reached such a degree of perfection that it is possible to speak of crucial experiments— experiments designed to give an answer in terms of better under- stood relations. In embryology, on the contrary, the experimental work appears crude in comparison. Nevertheless, the more exact experimental sciences have also passed through such beginnings, and on the borderland of physics and chemistry, where new prin- ciples may be met with, the experiments may also be little more than a preliminary testing out of possibilities. In fact, it might be argued, I think, that the famous experimentwn crucis is some- thing of a bogie, for it is often not so much a method of research as a final and triumphant demonstration when all the pioneer work has come to a successful ending. It is not, I think, a disparagement of the experimental method in embryology to admit that, at its beginning, it is still little more than the adventurous exploration of a new field. The exploratory feature of preliminary experimental work often serves to suggest problems rather than to interpret them. In fact, it is often little more than an extension of observational work. Many of the