[119] 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). That is the first of our important negative statements about regulations; the second relates to the phrase just used, “or it does not occur at all.” There are indeed limits of regulability; adaptations are not possible to every sort of change of the physiological state: sickness and death could not exist if they were; nor is restitution possible in all cases where it might be useful. It is a well-known fact, that man is only able to heal wounds but is altogether destitute of the faculty of regeneration proper. But even lower animals may be without this faculty, as are the ctenophores and the nematodes for instance, and there is no sort of correspondence between the faculty of restitution and the place in the animal kingdom. It is not altogether impossible that there may be found, some day, certain conditions under which every organism is capable of restoring any missing part; but at present we know absolutely nothing about such conditions.[120] [120] Experiments carried out in the “Biologische Versuchsanstalt” at Vienna indeed have shown that many animal types are capable of at least a certain degree of restitution, although they had previously been denied this faculty by zoologists. But no amount of negative instances can disprove an existing positive--which is what we have been studying. Our analysis based upon the existence of regulations is as little disparaged by cases where no regulability exists as optical studies are by the fact that they cannot be undertaken in absolute darkness. *D.* INHERITANCE: SECOND PROOF OF THE AUTONOMY OF LIFE All organisms are endowed with the faculty of re-creating their own initial form of existence. In words similar to these Alexander Goette, it seems to me, has given the shortest and the best expression of the fact of inheritance. Indeed, if the initial form in all its essentials is re-created, it follows from the principle of univocality, that, *ceteris paribus*, it will behave again as it did when last it existed.