case of vision, as the soap advertisement of our boyhood with its complementary colours taught us. Taste manifests the same phenomenon, for which reason (so he says) the cheese-taster in Scotland swallows a little whisky after each of the different samples he tries. But, curiously enough, the healthy car is not thus dulled save by a very loud, persistent noise, and then there is the risk of permanent damage to the hearing organ. Some forms of tactile sensation, also, would seem to remain ever sensitive, for, although it may be possible to become so inured to pain as to ignore it, yet that is probably a mental act, and it is said, moreover, that men have been tortured to death by the tickling of the soles of their feet.
But, as we have already seen, of all the senses none so quickly becomes inert under stimulation as olfaction. Why it would be hard to say, unless, like the exhaustion of colour-vision, it is due to the using up of some chemical reagent in the sense-organ. At all events, if you wish to appreciate the full intensity of a smell, you should arrange to come upon it from the open air.
I wonder if this, or something like it, is the reason why England was the first country in the world to wage war against its stenches. For the English are of all races the most addicted to fresh air. Consequently, they are the most likely to keep habitually their olfactory sense unspoiled and
