PHYSIOLOGY. 
iid food. About tbe end of the first year 
he learns to stand on his feet, and to assume 
the erect posture, that most distinguishing 
attribute of the human body. 
When it has now been removed from the 
breast, and learned the use of the lower 
limbs, its powers and independence increase 
daily, and receive a vast accession from the 
developement of another peculiar privilege 
of the human subject, the enjoyment of 
speech ; by whicli the tongue, under the di- 
rection of the mind, pronounces those ideas 
which are now become familiar. 
At the seventh year the twenty milk teeth 
begin to fall out, and are succeeded in a 
giadnal progress during the following years 
by the thirty-two permanent teeth. At this 
time the memory excels all the other facul- 
ties of the mind ; whereas about the fifteenth 
year the powers of imagination begin to 
prevail. This is the time of puberty, in 
which the human subject is gradually pre- 
pared, by various important changes, for 
the exercise of the sexual functions. The 
breasts enlarge in the female, the chin be- 
comes covered with hair in the male, and 
other similar signs of pubertjr are noticed in 
both sexes. The menstrual discharge com- 
mences in the softer sex ; and this impor- 
tant era in the economy of the female is 
marked by an increased expression in the 
eyes, and redness of the lips, ' and more ma- 
nifest sensible qualities in the matter of per- 
spiration. The seminal secretion becomes 
active in the male, attended with an in- 
crease of the beard, and a deepening of the 
voice consequent on a remarkable develope- 
ment of the larynx. The internal and 
spontaneous calls of nature now rouze the 
sexual instinct, for the exertion of which 
both sexes are prepared. 
No definite and precise period can be 
assigned for the changes which constitute 
puberty : it varies according to climate and 
temperament. It is more early in the fe- 
male than in the male ; but in this climate 
girls may be said to attain it at the age of 
fourteen or fifteen, and men at seventeen 
or eighteen. Soon after these periods the 
growth of the body is completed ; the sta- 
ture of which varies much in different 
races, not to mention its varieties in indi- 
viduals and families. The epiphyses, which 
have hitherto been distinct from the body 
of the bone, are now completely consoli- 
dated with it. . 
Virility Manhood, or Adult Age, begins 
from the twenty-first to the twenty-fifth 
VOL. V. 
year. If the increase of the body in height 
have ceased at this time, it grows in other 
dimensions. The organs become firm and 
consistent -, their functions are performed 
with vigour ; the intellectual and moral fa- 
culties are perfected ; and the dominion of 
the judgment succeeds that of the imagina- 
tion. This period, which is called that of 
mature age, extends to the fiftieth or fifty- 
fifth year in men, but not much beyond the 
forty-fifth in women, in whom it begins ear- 
lier. During this long interval men enjoy 
all the plenitude of their existence. 
Temperaments. As the characters of the 
human species are now fixed with stability, 
we may sketch the differences which mark 
individuals. Health, in the explanation of 
w'hich all physiology is concerned, consists 
in such a harmony and equilibrium of the 
material fabric of the body, and of its ani- 
mating powers, as is necessary for the per- 
formance of the various functions. It re- 
quires, therefore, fluids rightly prepared; 
solids duly formed from these ; the latter 
thoroughly animated by their vital powers ; 
and, lastly, a sound mind in this healthy 
body. These four principles are constantly 
acting and re-acting in the human body. The 
fluids act as stimuli on the solids; W'hich 
possess vital powers, enabling them to re- 
ceive those stimuli, and to re-act. The 
connection of the mind and body is not dis- 
cerned merely in the influence of the will, in 
what physiologists call voluntary actions ; 
since the affections of the body clearly act 
on the mind in many other ways than through 
the medium of sensual perceptions. The 
infinitely varied modifications, which the 
four principles admit of, show immediately 
with what latitude our notions concerning 
health should be formed. Hence arises 
the distinction of temperaments ; that is, 
the different manner in w’hieh the living so- 
lid is affected by stimuli, particularly of the 
mental class, the different aptitude for such 
impressions, and the greater or less facility 
with which these stimuli may themselves bo 
excited. There is such great variety of de- 
grees and combinations of temperaments, 
that a wide field is open for those who wish 
to employ themselves in dividing and ar- 
ranging them. The common division is suf- 
ficient for our purpose ; it comprehends the 
sanguineous, which is very easily but slightly 
affected by stimuli’; the choleric, which is 
easily and strongly excited ; the melancho- 
lic, which is slowly but deeply moved ; and 
the phlegmatic, which is the slowest of all 
Bb 
