oily skins give off various aromatic smells, none of which are valued by man. Toads have distinct odours, and one kind (_Pelobates fuscus_, or the heel-clawed toad), common in Europe, but not British, is known locally as the garlic toad on account of its smell. There are amongst carnivorous mammals various smells allied to that of civet which are not so agreeable to man as that substance; for instance, the odour of the fox and of the badger, and yet more celebrated, the terrible, awe-inspiring smell of the fluid emitted in self-defence by the skunk from a sac in the hinder part of the body. Horses, cows, goats, sheep, and the giraffe have their distinctive odours. Many of the herbivorous animals secrete a colourless fluid from large glands opening on or near the feet, and also from a gland in front of the eye (similar glands occur in other strange positions), which has not a smell familiar to man--that is to say, not one which has been recognised and described--yet seems to be readily "smelt" by the animals of its own kind. The bats--especially the large frugivorous bats--have a very unpleasant, frowsy smell. An important fact about animal smells is that many which we might be inclined to attribute to the animal which diffuses them, are really due to the fermentative or putrefactive action of bacteria which swarm on the skin and in the intestines of animals. It is often difficult to decide how far a peculiar animal odour is due directly to a substance secreted by the animal, and how far the odour of that substance is modified or even entirely produced by the chemical changes set up in secretions of the body-surface by bacteria. Several distinct repulsive smells liable to occur on the human body are due to want of cleanliness in destroying bacteria by proper antiseptics. The fatty and waxy secretions of the skin are often decomposed by bacteria, even before complete extrusion from the glands in which they are formed, whilst the decomposition of food in the mouth and intestines by bacteria alters materially both the natural odour of the animal's breath and the smell of the intestinal contents. In young and healthy animals in natural conditions there is some check--it is not easy to say what--upon the putrefactive activities of the omnipresent bacteria. The skin of a healthy young animal has a pleasant odour, and its breath (notably in the case of the cow and the giraffe) is naturally sweet-smelling. The same should be the case, under perfectly healthy conditions, with human beings.