ABSTRACTS
75
In trying to combat this belief, the author proceeds to explain in the first place,
that no sustainable scientific explanation has been advanced in support of telegony.
Among the various theories that have been advanced in its favour, critical examination
is made of one that is mostly in vogue, namely, the saturation hypothesis. According
to this hypothesis the foetus has in its blood special properties derived from the father
and on account of the existence of exchange between the maternal and foetal blood, the
constitution of the mother may be affected with the result that subsequent offsprings by
another father may be influenced. But this conception is directly opposed to the well
established chromogenic theory of heredity. In conducting experiments in animal gene-
tics with cross breds, particularly with reference to the transmission of a dominant
character, it is found that the sex-cells are not influenced by the bodily peculiarities of the
animal which lodges them. No more direct evidence is required to show that the bodily
peculiarities of an animal do not circulate in its blood in any form. Such being the case-
it is all the more unconceivable that the farther removed embryo could have any influence
on the sex-cells of its host.
Besides, experiments carefully planned to investigate the problem of telegony, under-
taken by various workers with a view to reconstruct certain remarkable cases that had
seemed to demonstrate the existence of telegony, had always failed to yield positive results.
Nevertheless, the fact remains, that certain observations, examples of which have
been given above, have appeared to uphold the existence of telegony. The author ex-
plains that while these facts are authentic their explanation has been faulty. Their
true explanation is to be found in the Mendelian law of heredity.
The Mendelian law of heredity shows that there is not always agreement between the
external characters of an individual (phenotype), and those which it can transmit to its
descendants (genotype). According to circumstance, there is, or there is not, agreement
between the phenotype and the genotype. A parent with a long line of ancestors selected
for the same attributes shall transmit all these attributes with constancy when it is served
with the same stock as itself. In this case the virtues or shortcomings displayed truely
correspond to the qualities which it will transmit to its descendants : here there is agree-
ment between the phenotype and the genotype. On the contrary, let one take an in-
dividual born out of the crossing of two individuals of different races. It is possible that
it remarkably resembles one of its parents. Nevertheless one knows that not only it can,
but must, certainly transmit to its descendants such attributes that it did not externally
display, but which have been held in latency in the sexual cells. In this case there is
disagreement between the phenotype and the genotype. It is thus possible sometimes,
that bodily peculiarities of an ancestor may sometimes make their appearance in an off-
spring removed by several generations.
The author quotes as an example the case of the crossing of a grey mouse of pure
breed with a white mouse. Greyness being the dominant colour, the young ones will be
grey like the grey parent. These grey cross-bred descendants, served between them-
selves, will always give a fourth of white mice. This phenomenon is constant. A cross-
bred grey mouse, if covered by a white male, will give according to the Mendelian law,
half of grey ones and half of white ones. If this same cross-bred grey mouse were
served afterwards with a grey cross-bred male, she will give as aforesaid, a fourth of