Note 119 — THE INDIVIDUAL ORGANISM WITH REGARD TO FORM AND METABOLISM (continued 3)

The few cases of an “improvement” of morphogenetic acts in hydroids described by myself are too isolated at present to be more than mere problems (Arch. Entw. Mech. 5, 1897). The same is true, it seems to me, with regard to certain recent discoveries made by R. Pearl on Ceratophyllum (Carnegie Inst. Wash. Publ. No. 58, 1907); and by Zeleny on a medusa (Journ. exp. Zool. 5, 1907). Pawlow’s discovery, that the enzymotic composition of the pancreatic fluid in dogs becomes more and more adapted to a specific composition of the food (either meat or bread and milk) the longer such a specific composition is offered to the individual animal, may probably be understood as a case of mere functional adaptation of the cells of the digestive glands, if it stands criticism at all (see Bayliss and Starling, Ergeb. Physiol. 5, 1906, p. 682).