TRANSACTIONS OF SECTION I. 669 
MONDAY, SEPTEMBER 15. 
Joint Meeting with Section M. 
The following Papers were read :— 
1. The Measurement and the Significance of the Hydrogen Ion 
Concentration in Biological Processes. By Professor S. P. L. 
SORENSEN. 
2. Discussion on the Physiology of Reproduction. 
(i) The Application of Generative Physiology to Animal Husbandry. 
By K. J. J. Macxenzin, M.A. 
In the regrettable absence of Dr. F. H. A. Marshall, it is proposed to open 
the discussion from the point of view of the practising agriculturist. The breed- 
ing of live stock on the farm has, it is contended, been carried on for many gene- 
rations without any very great measure of assistance from the man of science. 
That the practical breeder’s efforts have, on the whole, been successful is not 
in any way denied—on the contrary, the skill of the practitioner cannot fail to fill 
the observer with admiration—but it is hoped that this discussion may bring to 
the notice of physiologists and zoologists some points which demand further 
scientific investigation. To illustrate this statement some work already done by 
Dr. F. H. A. Marshall, in association with the speaker, may be instanced as 
showing that scientific investigation can throw light on the practical difficulties 
of the breeder and manufacturer. The bacon-curer at the present moment incurs 
great loss owing to the prevalence of a considerable number of carcases which, 
on examination immediately after slaughter, are found to have a very valuable 
‘cut’ or joint spoilt by discoloration. One firm of bacon manufacturers esti- 
mate their Joss from this cause to be several thousand pounds sterling per 
annum. The popular belief among breeders and manufacturers is that dis- 
coloration is due to cestrous changes. It was suggested that ovariotomy pre- 
vented this discoloration from appearing. On investigation, the discoloration 
has been found to be a matter of pigmentation, and that though ‘spaying ’—as 
ovariotomy is called by the farmer—may be useful in other ways, it has little, 
if any, effect in reducing the evil complained of. Having this knowledge, the 
problem can now be attacked with greater chance of success. Incidentally, whilst 
working on this problem, Dr. Marshall’s investigations into the estrous cycle in 
the sow have thrown light on a practical matter in connection with the breeding 
of swine. A scientific reason has been found, upholding the opinion held by some 
few only of the very experienced breeders that male and female pigs should be 
mated at a particular time. In this case science should be of value to the 
farmer, for up to now the opinion formed on empirical observation has not been 
strong enough to guide his practice in a direction which involved slightly more 
trouble. 
The frequent occurrence of impotency among sires is a matter in which a long 
experience of farm animals, and a very inconvenient incident of recent date, 
force one to the conclusion that scientific research might be usefully employed 
on behalf of the agriculturist. 
Impotence in the male may be temporary or permanent. It is often of in- 
calculable value to the farmer to know which of these two states exists. Yet it 
would seem that scientific knowledge is such that only too often the farmer is 
left to let time decide. Work done with a view to seeing if it be possible to 
give the agriculturist advice about a doubtful sire before it reaches the slaughter- 
house seems to be demanded. Temporary sterility may, it seems reasonable to 
believe, be caused by over-service, bad management, mal-nutrition, or other 
causes. It appears desirable to investigate all conditions governing this state, in 
the hopes of becoming competent to advise an agriculturist, who often would 
