60 Experimental Zoology 
The best-known case, and one that Darwin himself believed 
to have been “‘perfectly well ascertained,” is that of Lord Mor- 
ton’s mare, a full account of which is given in Darwin’s “ Ani- 
mals and Plants.” A pure Arabian mare was bred to a 
quagga, and the first offspring was, of course, a hybrid. The 
second time, the mare was bred to a stallion of pure stock. 
The colt showed cross markings on the legs, that were said to 
be much more developed than on colts of pure pedigree. Dar- 
win thought the evidence sufficient to show that in some 
unknown way the mother had been affected, either by the 
sperm of the quagga or by the hybrid embryo zm wiero, and this 
effect was again in some unknown way transmitted to the sec- 
ond offspring. Darwin advanced this case as one of several in 
support of his hypothesis of pangenests. 
The statements remained practically undisputed until within 
recent years. A few years ago Ewart undertook to repeat the 
experiment, which he was enabled to do by having a small 
experimental farm placed at his disposal. Careful series of 
cross-breeding experiments, followed by pure breeding, were 
carried out. Ewart discusses his results in his book entitled 
“The Penycuik Experiments,” and reaches the conclusion that 
no clear evidence of infection, if I may so call it, can be pro- 
duced in this way. He also points out that it is not uncommon 
for colts, purely bred, to show stripes as distinct as those in Lord 
Morton’s case. Fortunately a picture of this colt is still in ex- 
istence, and its examination shows that the markings are not 
more distinct than those that sometimes occur in the case of 
purely bred animals. There was, then, merely a coincidence, 
and not a causal connection. 
Bell has given an excellent summary of the evidence in regard 
to the possible influence of a previous sire, and has carried out 
a number of experiments on horses and dogs. In none of 
these cases was any influence of the previous progeny.or of a 
1 Two other cases were reported to Bell, one for pigeons and the other for a 
cross between a negro and a white woman. In neither case were the later off- 
spring, by a father of their own kind, affected by the first union. 
