The desire to reproduce is not constant in the dog, but occurs at periods varying in individuals even of the same variety, in some as often as every six months; but whether six, seven, or eight months, the period is generally kept to with tolerable regularity, so that an observant breeder who keeps a kennel record can tell pretty nearly when his bitches will be in season.

It is not necessary to describe in detail the symptoms of heat - there is general disturbance and excitement of the whole system; it is, I believe, in many instances possible to tell by the eye of the dog, certainly the expression is altered, as well as the manners and action. Often, with the careless owner, the fact first becomes evident to him by the nuisance of a pack of strange dogs about the place, making night hideous by occasional prolonged sounds, between a howl and a whine; but before that he should have been aware of a change in his dog, and have kept her up. On examination the external organs of generation are seen to be enlarged and vascular, and for some days, about the middle of the time, there is bleeding from the vulva; when this has stopped is by most breeders considered the most favourable time for her to visit the selected mate; the period of heat lasts about three weeks.

Thirst is an accompaniment of heat, and the bitch should have access to water constantly. If it is not intended that she should breed, care must be taken to keep her locked up, for many show great cunning at this time, and will not miss a chance to steal away and seek mates for themselves. If not intended to breed it is absolutely necessary she should have cooling medicine - a dose of ordinary black draught answers well, and may be given twice a week; the food, too, should now be light, and the proportion of vegetables increased and flesh meat decreased. This course will often prevent fits, which, in those predisposed to them are apt to appear at this time.

When the bitch has been kept up there will, in all probability, at the end of the usual period of gestation - nine weeks - be a secretion of milk. This should be drawn off, or the accumulation in the teats and other lactiferous glands will produce indurations ending in tumours. The mammae should in such cases be bathed with warm water, and afterwards rubbed with camphorated oil, or, if there is much heat and swelling, add to the camphorated oil one-third part of brandy and the same proportion of spirit of hartshorn. At the same time recourse should be had to doses of black draught twice a week and a light diet.

It is a practice too general to keep bitches year after year and prevent them from breeding. This is strongly to be condemned. It appears to me an unjustifiable interference with nature, and it is certain that the consequences to the animal are seriously detrimental. Not only are they from this cause liable to suffer from scirrhous tumours, but it begets a plethoric state of body and partial deposits of fat around the ovaries and elsewhere that interferes with the healthy functional operations of important parts, and leads often to acute disease, and, where life is prolonged, it is as a burden to the dog and a nuisance to her owner.

Breeding is a natural, healthy, and necessary thing. It is specially required by highly fed dogs living luxuriously, as a means of using up their excess stock of material, and, therefore, all bitches should be allowed to breed at least occasionally.