792 THE POPULAR SCIENCE MONTHLY. 



comes most quickly conscious of peril, and will outlive, as a rule, the 

 one whose sensations have a longer distance to travel. 



It can be easily shown that the mouth and the organs of taste and 

 smell are as necessarily confined to the head, and that their special 

 location is closely governed by that of the eyes. 



For animals have safety of two kinds to provide for, safety from 

 foes and safety from food ; external and internal perils. Poisonous or 

 unwholesome food is quite as necessary to be avoided as dangerous 

 foes. The animal that is best protected against this peril has the best 

 chance to survive. So important, indeed, is this necessity, that not 

 alone the sight and the sense of touch and of temperature are on guard 

 against injury from such a source, but two organs of sense, smell and 

 taste, seem specially provided for this purpose alone. 



The needful action of the eyes, as food-inspectors for the body, 

 fixes the position of the mouth at such a distance from them that they 

 will unavoidably perceive the food. Animals are not likely to volun- 

 tarily examine their food before eating it. They must be forced to 

 do so involuntarily. Therefore, the eyes naturally command the en- 

 trance to the mouth, at the best distance for the most acute vision. 



The relative positions of eyes and mouth being thus fixed, those of 

 the smell and taste organs follow. Odorous emanations arise from 

 the food significant of its character. The animal becoming most con- 

 scious of them has the best chance to escape danger. These odors nat- 

 urally rise upward. The nose, as the organ of smell, is therefore best 

 situated just above the mouth, and overhanging it, the performance of 

 its function, as the organ of respiration, causing the respired air to 

 sweep the lips and draw in the odors arising from the food. 



The organ of taste, on the contrary, is best situated on the rear 

 portion of the tongue, since the food must be masticated by the 

 teeth, and partly dissolved by the saliva, ere it is in condition to 

 excite the sense of taste. It must not be placed so far back, how- 

 ever, as to hinder the rejection of food warned against by the nerves 

 of taste. 



The head of the animal, then, seems necessarily to be just as we 

 find it, the seat of the special senses and of the brain ; while the rela- 

 tive location of these sense-organs and of the mouth, the position and 

 elevation of the head, and the narrowness and flexibility of the neck, 

 appear to be all necessary adaptations for the most complete protection 

 of the whole organism. 



The mammalian body, then, so far as we have yet seen, appears the 

 best adapted of animal forms to gain extended and varied experiences 

 of nature, to become exposed to diversified perils, and to evolve the 

 most complete division of function. This body, once attained, is closely 

 adhered to. "While displaying thousands of minor variations, adapt- 

 ing it to special circumstances, it retains unvaryingly all the general 

 characteristics mentioned. This close adherence seems to show that 



