MAMMALIA—MAN. oD 
during any other season of life. The pulse is certainly strong, and it is 
therefore fair to conclude, that the internal heat is considerabie. Till the 
age of three years, the life of infants is extremely precarious ; in the course 
of the ensuing second and third years, it becomes more certain, and at six 
or seven, a child has a greater probability of living than at any other period 
of life. It is remarked, that of a certain number of children born at the 
same time, above a fourth die in the first year, above a third in two years, 
and at least one half in three years. By other calculations, it appears that 
one half of the children born at the same time, are not extinct in less than 
seven or eight years. 
At twelve or fifteen months, infants begin to lisp. The broad sound of A, 
is the first sound which they articulate with most ease. Of the consonants, 
B, M, P, T, are most easy. In every language, therefore, baba, mama, papa, 
are the first words that children learn. Some children pronounce distinctly 
in two years, though the generality do not talk for two years and a half, 
and frequently not so early. 
Some persons cease growing at fourteen or fifteen, while others continue 
their growth to twenty-two or twenty-three. In men, the body attains its 
perfect proportion at the age of thirty, and in women sooner. The persons 
of women are, indeed, generally complete at twenty. The distance between 
the eyes is less in man than in any other animal ; in some creatures, in fact, 
the eyes are at so great a distance, that it is impossible they should ever 
view the same object with both eyes at once. Men and apes are the only 
animals that have eyelashes on the lower eyelid. Other animals have 
them on the upper, but want them on the lower lid. The upper lid rises 
and falls, the lower has scarcely any motion. 
The ancients erroneously considered the hair as a kind of excretion, and 
believed that, like the nails, it increased by the lower part putting out the 
extremity ; but the moderns have discovered that every hair is a tube, which 
fills and receives nutriment, like the other parts of the body. The roots, 
they observe, do not turn gray sooner than the extremities, but the whole 
changes color at once. Instances have been known, of persons who have 
grown gray in one night. 
There is little known exactly with regard to the proportions of the human 
figure ; and the beauty of the best statues is better conceived by observation 
than by measurement. Some, who have studied after the ancient masters, 
divide the body into ten times the length of the face, and others into eight. 
They tell us that there is a similitude of proportion in different parts of the 
body: thus, that the hand is the length of the face; that the thumb is the 
length of the nose; that the space between the eyes is the breadth of the 
eye ; that the breadth of the thickest part of the thigh is double that of the 
thickest part of the leg, and treble the smaliest; that the arms extended 
are as long as the figure is high. 
