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Is there a quantitative addition of internal glandular tendencies in the germplasm, or a more complex rearrangement dependent upon reactions between all the internal secretions? The term endocrine dominants brings up the inquiries of Mendelism, and the relation of Mendelian conceptions of dominant and recessive to the internal secretions.
The trouble with this generalization, from the modern Mendelian point of view, is that it fails to define what "characters" one would get in the one-half that came from one's parents, or the one-fourth from one's grandparents. The whole of our inheritance is not composed of these indefinitely made up fractional parts.
The Mendelian merely sees a relation of the character to sex, but overlooks entirely the question of the dimorphism in the original species from which the domesticated breeds are descended.
In Mendelian experiments, a heterozygote individual is one arising from gametes containing opposite members of a pair of characters, in other words, from the union of a gamete carrying a dominant with another carrying a recessive. A pure recessive individual is one arising from the union of two gametes both carrying recessives.
Their being functional, and hence to all external appearances normal, would cause such animals to escape observation. Latent traits of the opposite sex of course immediately suggest recessive or unexpressed characters in the well-known Mendelian inheritance phenomena.
Again we get our three-to-one Mendelian ratio, but this time it is three hornless to one horned. Especially Goldschmidt's carefully graded experiments point to a similar difference in the strength of the dose or doses of the sex factors.
There is a further point in connection with Mendelian theories which is worth noting in this connection. It would appear that no new factor is ever brought into being, that is, no addition is ever made by variation. According to this theory the things which appear to be added a new colour or a new scent were there all the time.
The Mendelian theory therefore is that when an ovum has two X sex-chromosomes it can only after a number of cell-divisions, at the following reduction division, give rise to ova, while an ovum containing one X sex-chromosome, or two different, XY, chromosomes, at the next reduction division gives rise to spermatozoa.
This argument assumes that the secondary characters are essentially of sexual nature without inquiring how they came to be connected with sex, and it ignores the fact that the influence of castration on such characters is a phenomenon entirely beyond the scope of Mendelian principles altogether.
The seeds of this dwarf repeated the variety in the next generation, but in the third none were observed. Then the variety was thought to be lost, and the culture was given up, as the Mendelian law of the splitting of varietal hybrids was not known.
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