366 
PHARMACEUTICAL SOCIETY, EDINBURGH. 
its bulk and to the replenishment of the wear and tear, hut it also supplies a certain amount 
of force, which the animal avails itself of when asleep and when awake, and on which it 
relies for the bodily strength it possesses, and for the force it exerts in daily work for 
daily bread. And it has become equally apparent that the Pharmaceutic preparation 
performs its important functions in the animal economy, by directing and controlling 
the animal functions, and assisting the vital powers to remove impediments which retard 
the changes which are consistent with proper health. The animal frame is in a state of 
incessant change, and demands not only that the vacancies in the structure should be 
filled in, but that the useless decayed matter should be removed. Diminution of the 
supply necessarily leads to impoverishment of blood and body, and delay in removal of 
used up matter leads to contamination of blood and unhealthiness of body. 
The numberless transformations which are daily occurring in the animal structure are 
directed or controlled by vital activity or vitality, which is the pilot or helmsman which 
guides the matter and force in their sojourn through the animal economy. Many of the 
changes which occur in the bodily frame, which were a few years ago regarded as mys¬ 
terious, are now explained by physical and chemical laws, and much that still has 
baffled the insight of man will undoubtedly be unveiled in years to come. 
No man of intelligence believes it possible that human ingenuity will ever succeed to 
grapple with dead matter and impart life to it, but it is undoubted that the vital 
activity displayed by an animal when once created by the Designer and Upholder of the 
universe, can be influenced materially by natural forces, and is much under the control 
of outward circumstances. The forces which more or less influence vital activity are 
heat, light, electricity, magnetism, and chemical affinity, and both externally and inter¬ 
nally they perform important functions, and must be regarded as necessary stimuli. 
Heat is a most important force in relation to vital phenomena. The higher animals 
are much influenced by sudden elevations or depressions in temperature. Birds which 
have an average warmth of 110° Fahr., when reduced to about 80° Fahr. succumb to the 
effects of the cold, and man and other mammalia which have a temperature ranging 
from 98° to 102°, cannot generally be reduced below 70° Fahr. without fatal consequences 
ensuing. The majority of the higher animals can conform to circumstances of external 
heat and cold, and by the development of more or less internal heat counterbalance, to- 
some extent at least, for the external variations in temperature. But where the supply 
of combustible matter within the living structure is sparing in quantity, and starvation 
\ ensues, the internal source of heat day by day decreases in amount, and correspondingly 
the vital activity becomes less powerful, and dwindles away till the flame of life flickers 
and then dies out. Before the last stage has been reached, artificial heat from external 
sources may revive the vital activity for the time, but where the production of heat in¬ 
ternally has almost failed, the vitality of the animal sinks and sinks till it is extinguished. 
There are some exceptions to the rule, that decrease in temperature for 30° below the 
normal heat proves antagonistic to the sustainment of vitality. Thus the polar bear and 
marmot, having laid up a store of fat or combustible matter, can pass into a hybernating 
state—a condition of torpor or sleep, and live for months in a state of dormant vitality,, 
where the pulsations decrease from 150 to 15 per minute, or -J^th of the whole, and the 
respirations, which number in active life 500, fall to 14 per hour; whilst the temperature 
of the body may be reduced to within 2° or 3° of the freezing-point of water. These 
hybernating animals awake from their condition of dormant vitality when the tempera¬ 
ture of the air rises, and renew their vigour, having only lost during their long sleep the 
store of fat which they formerly possessed. All animal functions proceed more or less 
quickly as the temperature is increased to a reasonable extent; and the stimulus which 
external heat imparts to animal vigour may be well illustrated in the Triton, or water 
newt, which when it loses a limb cannot restore it at low or winter temperatures, but 
in summer weather, when the temperature ranges from 58° to 75° Fahr., the Triton pro¬ 
ceeds to make a speedy restoration of the lost limb. Another illustration of the effect 
of external heat in giving a stimulus to vital activity is observed in the hatching of 
the eggs of birds as well as those of serpents, where at ordinary temperatures the vi¬ 
tality of the germ lies dormant, and is only stimulated to action by the continued in¬ 
fluence of a higher temperature. 
Light also exerts its stimulating powers in vital activity. In the vegetable kingdom 
the absence of light is denoted by a sickly growth and a blanched aspect, and by the 
want of that solidity of structure and healthiness of stem and root which the plant ex- 
