In the organisms described above, the chemical, or, more specifically, the taste, sense is a food sense,—edible and inedible substances causing reactions of different character. The reactions to stimuli within the edible group, however, show no variation. In the insects, especially the ants, bees, wasps, etc., there seem to be qualitative differences in the effect produced by chemical substances. It is by means of this chemical sense that bees and ants are able to find food at a distance, to return to their homes under all sorts of adverse conditions, and to distinguish nest mates from enemy intruders. But, since these are all reactions to stimuli at a distance, they must be attributed to the smell sense, rather than to the taste sense. But in the case of these organisms a sharp distinction between smell and taste seems possible. Forel and others have offered honey mixed with strychnine to ants, who seized it greedily, indicating an olfactory sensibility. But immediately after the honey had touched the mouth parts, avoiding reactions, such as to remove the substance, followed, indicating sensitiveness to the bitter substance. Wasps and bees will make the same sort of responses if distasteful substances which are inodorous are mixed with pleasant, odorous substances. The sensitivity to tastes varies considerably in different insects, being very great in bees and ants. From such experiments as the above it has been concluded that the smell organs are located on the antennæ and that the taste organs are located on the lips and in the mouth. Microscopical examination shows that in all insects the tongue and inside of the mouth are covered with minute pits, or depressions. In each pit there is a minute hair, or rod. Some observers say that this rod is hollow and perforated at the end, thus communicating with the nerve which ends at its base. Other observers say that there is no perforation upon the end of the hair. However this may be, there seems to be no doubt that these are the taste organs. The same type of structure has been reported on the proboscis of the bumblebee, the hive bee, and the common fly. They are said to resemble a hollow hair, the channel communicating with a nerve fiber at its base. In the insects, then, we find the earliest definitely specialized taste mechanism. _Chemical Sense in Fishes_