Mr Heape, Notes on the Proportion of the Sexes in Dogs. 123 
is at least true for the ova, and that both contain within them- 
selves definite sexual characteristics. 
Now regarding the product of these generative elements. 
An animal is not necessarily purely male or female ; on the 
contrary, notwithstanding the evidence adduced by Punnett, for 
instance (“ Sex determination in Hydatina with some remarks on 
Parthenogenesis,” Proc. Roy. Soc., vol. 78, 1906) which seems to 
me probably capable of other interpretation, I will venture to 
maintain there is no such thing as a pure male or female animal, 
but that all contain a dominant and recessive sex, except those 
hermaphrodites in which both sexes are equally represented. 
The appearance of recessive male characteristics in adult 
dominant females and of recessive female characteristics in adult 
dominant males, among unisexual animals, is of undoubted occur- 
rence and not only from a structural point of view. I suggest 
therefore that this fact, together with various known examples of 
more pronounced dual sexuality ; such as, for instance, the ability 
possessed by the male sexual gland of certain unisexual animals, 
under certain conditions, to produce ova (Potts “ The modification 
of the sexual characters of the Hermit crab caused by the parasite 
Peltogaster,” Quart. Journ. of Mic. Sci., vol. 50, 1906) ; and the 
normal production of true hermaphrodites ; is proof that all 
animals contain the elements of both sexes in some degree. 
I should perhaps here point out that Potts’ results do not 
show that the sex of the animal is changed by the parasite, but 
rather that the recessive sex present in the animal is thus 
stimulated. The structural modifications which accompany the 
changes in the generative glands indicate the close correlation of 
primary and secondary sexual characteristics. 
In this relation the experiments of Bordage (quoted by Castle 
“ The Heredity of Sex,” Bull. Mus. Comp. Zool. Harvard, vol. 40, 
1903) are of interest ; they show that cutting back the apex of a 
young male plant of Carica pupaya just before the appearance of 
the male flower, may result in the growth of two branches from 
below the cut which bear female flowers and fruit. Also the 
observations of Strasburger ( Biolog . Centralblatt, 1900) on the 
effect of rust fungus on the female flowers of Lychnis dioica, 
resulting in the development of stamens normally reduced to 
rudiments ; and those of Meehan on the “ Relation of heat to the 
sexes of flowers” {Proc. Acad. Nat. Sci. Philadelphia, 1882 — 1884), 
may be similarly interpreted. These observations are all indica- 
tive of the result of stimulation of the recessive sex, either directly, 
or indirectly on account of the functional degeneration of the 
dominant sex. 
Much evidence advanced by Castle {loc. cit.) is of great interest 
in reference to this portion of the subject, and I regret that the 
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