The biology of the internal secretions : the endocrine factor in development, in subnormalities, in neoplasms and malignancy, in nervous and mental diseases and in heredity / by Francis X. Dercum.

  • Dercum, Francis X. (Francis Xavier), 1856-1931.
Date:
1924
Catalogue details

Licence: In copyright

Credit: The biology of the internal secretions : the endocrine factor in development, in subnormalities, in neoplasms and malignancy, in nervous and mental diseases and in heredity / by Francis X. Dercum. Source: Wellcome Collection.

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    suggests itself in this connection, but the com¬ parison ceases here, as in these animals the external layer develops no special nervous area. It is, however, the mesoderm—absent in the coelenterates—which now especially invites our attention. The mesoderm, or mesenchyme, a name which in some respects is to be preferred, is a layer the cells of which, doubtless because of their independence both of external rela¬ tions and of the intake of food, retain, more than the cells of either of the other layers, the generalized properties of the simple, primordial, undifferentiated cell, and, in consequence, re¬ veal the most marvelous polymorphic pos¬ sibilities. Lymph and blood, heart and ves¬ sels, muscle and bone, connective tissue, the major portion of the sympathetic nervous sys¬ tem, various glandular structures, all have their origin in this layer. A discussion of how these structures are differentiated would take us too far afield. It is not the object of this essay to trace the details of organic evolution as re¬ vealed by embryology, but merely to consider such facts as have a bearing upon the internal secretions. 3