BIOLOGICAL BEGINNINGS 25 



gradually lost the power of moving them. This would be a parallel case 

 with that of those large and heavy birds, which from inhabiting oceanic 

 islands, have not been exposed to the attacks of beasts of prey, and have 

 consequently lost the power of using their wings for flight. The inabihty 

 to move the ears in man and several apes is, however, partly compensated 

 by the freedom with which they can move the head in a horizontal plane, 

 so as to catch sounds from all directions. 



The nictitating membrane, or third eyelid, with its accessory muscles 

 and other structures, is especially well developed in birds, and is of much 

 functional importance to them, as it can be rapidly drawn across the whole 

 eye-ball. It is found in some reptiles and amphibians, and in certain fishes, 

 as in sharks. It is fairly well developed in the two lower divisions of the 

 mammalian series, namely, in the monotremata and marsupials, and in 

 some few of the higher mammals, as in the walrus. But in man, the quad- 

 rumana, and most other mammals, it exists, as is admitted by all anatomists, 

 as a mere rudiment, called the semilunar fold. 



The sense of smell is of the highest importance to the greater number 

 of mammals — to some, as the ruminants, in warning them of danger; to 

 others, as the carnivora, in finding their prey; to others, again, as the wild 

 boar, for both purposes combined. But the sense of smell is of extremely 

 slight service, if any, even to the dark coloured races of men, in whom it 

 is much more highly developed than in the white and civilized races. Never- 

 theless it does not warn them of danger, nor guide them to their food; nor 

 does it prevent the Esquimaux from sleeping in the most fetid atmosphere, 

 nor many savages from eating half-putrid meat. In Europeans the power 

 differs greatly in different individuals, as I am assured by an eminent na- 

 turalist who possesses this sense highly developed, and who has attended to 

 the subject. Those who believe in the principle of gradual evolution, will 

 not readily admit that the sense of smell in its present state was originally 

 acquired by man, as he now exists. He inherits the power in an enfeebled 

 and so far rudimentary condition, from some early progenitor, to whom 

 it was highly serviceable, and by whom it was continually used. In those 

 animals which have this sense highly developed, such as dogs and horses, the 

 recollection of persons and of places is strongly associated with their odour; 

 and we can thus perhaps understand how it is, as Dr. Maudsley has truly 

 remarked, that the sense of smell in man "is singularly effective in recalling 

 vividly the ideas and images of forgotten scenes and places." 



Man differs conspicuously from all the other Primates in being almost 

 naked. But a few short straggling hairs are found over the greater part 

 of the body in the man, and fine down on that of the woman. The different 

 races differ much in hairiness; and in the individuals of the same race the 

 hairs are highly variable, not only in abundance, but likewise in position; 

 thus in some Europeans the shoulders are quite naked, whilst in others they 

 bear thick tufts of hair. There can be Httle doubt that the hairs thus scat- 



