In this connection, I may say a word as to the curative value of organotherapy. Although, as I have shown to be the case, the transplantation of freshly extirpated genital glands into subjects of the opposite sex has no effect, it does not follow that the injection of the ovarian secretion into the blood of a male might not have a most injurious effect. On the other hand, the principle of organotherapy has been opposed on the ground that organic preparations procured from non-allied species could not possibly be expected to yield good results. It is more than likely that the medical exponents of organotherapy have lost many valuable discoveries in healing because of their neglect of the biological theory of idioplasm. The theory of an idioplasm, the presence of which gives the specific race characters to those tissues and cells which have lost the reproductive faculty, is by no means generally accepted. But at the least all must admit that the race characters are collected in the genital glands, and that if experiments with extracts from these are to provide more than a good tonic, the nearest possible relationship between the animals experimented upon must be observed. Parallel experiments might be made as to the effect of transplantation of the genital glands and injections of their extracts on two castrated cocks of the same strain. For instance, the effects of the transplantation of the testes of one of them into any other part of its own body or peritoneal cavity or into any similar part of the other cock might be compared with the effects of intravenous injection of testis extract of the one on the other. Such parallel investigations would also increase our knowledge as to the most suitable media and quantities of the extracts. It is also to be desired, from the theoretical point of view, that knowledge may be gained as to whether the internal secretion of the genital glands enters into chemical union with the protoplasm of the cells or whether it acts as a physiological stimulus independent of the quantity supplied. So far we know nothing that would enable us to come to a definite opinion on this point. The limited influence of the internal secretions of the sexual glands in forming the sexual characters must be realised to warrant the theory of a primary, generally slight, difference in each cell, but still determinate sexual influence.[2] If the existence of distinct graduations of these primary characteristics in all the cells and tissues can be recognised, there follow many important and far-reaching conclusions. The individual egg-cells and spermatozoa may be found to possess different degrees of maleness and femaleness, not only in different individuals, but in the ovaries and testes of the same individual, especially at different times; for instance, the spermatozoa differ in size and activity. We are still quite ignorant on these matters, as no one has worked on the requisite lines.