Mechanical action on the embryo may also give rise to pathological products or even mutilation. Thus, _Weismann_ demonstrated the production of degenerate individuals in ants when certain coleoptera were introduced in their nest, the ants being fond of the secretion of the large glandular hairs of the coleoptera. The exact cause of the degeneration has not yet been found, but the fact is certain. In man, certain constitutional affections and congenital anomalies are the result of certain diseases in the procreators, which have affected the germinal cells or the embryo (for instance syphilis). As soon as the blastophthoric actions cease in the procreators, those of their descendants who live under a normal regimen have evidently a tendency to eliminate the blastophthoric organs at the end of several generations and to regenerate themselves little by little. Thanks to the power of the ancestral mneme which tends to reëstablish homophony. However, the data on this subject are insufficient. In this case homophony is represented by the normal equilibrium of the different typical or normal characters of the species. FOOTNOTES: [1] I insert here some passages intended for more advanced readers, but this does not imply that they are of less importance. On the contrary I strongly advise all my readers to try and understand the theories of _Hering_ and _Semon_, which appear to me to throw a new light on the question of transformation and heredity. CHAPTER II EVOLUTION OR DESCENT OF LIVING ORGANISMS The theory of evolution is intimately associated with the name of _Darwin_, for it was he who established it in the scientific world. In reality, the idea of the transformation of organisms was put forward by _Lamarck_ more than a century ago, but he did not sufficiently support it. The theory of evolution states that the different animal and vegetable species are not each of them specially created as such from the first, but that they are connected with each other by a real and profound relationship, and derived progressively one from another; generally from more simple forms, by engraphia and selection. Man himself is no exception to this rule, for he is closely related to the higher apes. It is no longer possible to-day to deny the fundamental fact which we have just stated. Since _Darwin_, and as the result of the powerful impulse which this man of genius gave to natural science, innumerable observations and experiments have confirmed the truth of the progressive evolution of living beings. Comparative anatomy, comparative geography of plants and animals, comparative embryology, and the study of the morphology and biology of a number of recently discovered plants and animals, have built up more and more the genealogical tree, or _phylogeny_, of living beings, that is to say their ancestral lineage. The number of varieties and races or sub-species increases indefinitely, the more closely they are examined.