throughout much larger periods of time."[71:A] WHY CHILDREN RESEMBLE PARENTS.--That children reproduce the general and physical and mental characteristics of their parents in combination is unquestionable truth, although the particular mode in which they are communicated is yet undetermined, notwithstanding the fact mentioned by Professor Cope that they are somehow conveyed by the microscopic sperm and germ in the union of which the new being has its beginning. Thus every individual must possess the general characteristics of the primitive human family from which through a vast number of ancestors he has descended. And yet at every stage of descent the organism may have obtained fresh characters, or at least have undergone some modification. As remarked by Dr. G. H. Th. Eimer, "Every character which must have been formed through the activity of the organism is an acquired character. All characters, therefore, which have been developed by exertion are acquired, and these characters are inherited from generation to generation. The same holds for all organs atrophied through disease--the degree of atrophy is acquired and inherited. In the first class we see especially the action of direct adaptation; in the second, the results of the cessation of the action. A third class of acquired characters is to be traced simply to the immediate action of the environment on the organism, and, originally, at the commencement of their appearance, all characters must have belonged to this class."[72:A] We have here a general argument in opposition to the theory propounded by Professor Weismann, that acquired characters are not transmissible. Elsewhere (page 382) Dr. Eimer observes: "Phyletic growth, or the evolution of the organic world ever into higher and more complex forms, or at least into forms of different structure, is, as I have said, merely the sum of the processes of growth of the ancestors--together with the result of external influences on the forms during their development and their existence. This additional modification which the individuals as such undergo is--together with the influence of crossing--the very cause of the constantly progressing evolution. All that the members of a series of individuals directly connected by descent acquire constitutes together the material for the formation of a new species."