INA TROT: 
[JuLy 20, 1899 
THE PENYCUIK EXPERIMENTS} 
Pe well-devised breeding experiments now in pro- 
gress at Penycuik under the direction of Prof. 
J. Cossar Ewart, are, it need scarcely be said, of the 
accepted doctrines of fanciers and other breeders rest 
upon any firm scientific basis; and it is certainly most 
desirable that precise experiments should be undertaken 
with the sole object of arriving at the truth in such 
matters as prepotency, telegony and 
the effects of inbreeding. It cannot 
but be to the advantage of breeders 
if empiric methods founded on vague 
conjecture and imperfect generalis- 
ation can be made to give place to 
a rational system derived from exact 
knowledge of facts. Prof. Ewart’s 
design ought therefore to meet with 
a warm welcome in scientific and 
practical quarters alike. : 
The volume before us contains an 
account of such results of the author’s 
experiments as are now sufficiently 
mature for publication. It is not so 
much a book as a re-issue in book 
form of three papers that have al- 
ready seen the light, together with 
a general introduction which, to 
some extent, summarises and sup- 
plements the information subse- 
quently given. Prof. Ewart remarks 
that “as the problems under con- 
sideration are not of a kind that can 
be settled off-hand, and as one 
inquiry has begotten others, some 
years must elapse before a com- 
plete and systematic account is 
possible.” Meantime, he thinks, the 
publication of his results in their 
present form “will indicate the lines 
Fic. 1.—Matopo. 
along which the inquiries are pro- 
highest interest both theoretical and 
practical. To the general biologist 
the subject of hybridisation affords 
a wide field for the investigation of 
laws of heredity, and especially of 
such subsidiary factors, whether real 
or only imaginary, as reversion, pre- 
potency, saturation and telegony ; 
while the question of the sterility of 
hybrids has important bearings on 
the general theory of evolution. But 
besides the purely scientific aspects 
of the problems which are now being 
attacked by Prof. Ewart, there is 
also their practical application, which 
appeals with much force to the in- 
terests of the breeder of stock. It 
is of course true that the whole his- 
tory of animals and plants under 
domestication may be said to provide 
a body of experiments in these and 
similar subjects on a very large 
scale; and it is undoubtedly the 
case that many of the questions 
referred to have been already an- 
swered, at least provisionally. The 
experience of many generations of 
breeders has led to the emergence 
of certain practical rules, which are 
seldom if ever disregarded by those 
whose interests are concerned in the 
rearing of animals with a definite 
object. But it still remains doubtful how far the widely- 
1 “ The Penycuik Experiments.” By J.C. Ewart. M.D., F.R.S.. Regius 
Professor of Natural History, University of Edinburgh. Pp. xeiii + 177- 
(London : Adam and Charles Black, 1800-) 
NO. 1551, VOL. 60] 
Fic. 
2.—Romulus (seven days old) and his dam, Mulatto. 
ceeding, and also the kind of answers likely eventually 
to be made to some of the questions.” Regarded in this 
way as an instalment, the volume well fulfils its purpose. 
The first paper is chiefly devoted to a detailed descrip- 
+ 
