ORGANIC DEVELOPEMENT. 97 
95. The applications of the law laid down, seem to extend even to 
determining the number of germs which may proceed from different 
animals, and afford some data for ascertaining the amount of germi- 
nant force in each. We observe that the centres of reproduction are 
more numerous as the nervous system is smaller or less concentrated. 
The production of hair from the epidermis illustrates this fact; but a 
small portion of force and nutrition is brought to bear upon any one 
point, and these points are often exceedingly near, although varying 
according to the amount of vital force and nutrition. In the lowest 
animals, consisting of cellular tissue mostly, a concentrated nervous 
not effect, and this is generally admitted; and, if so, vitality must be considered one of 
the causes influencing chemical combinations. 
But it may be a question whether this vital influence admits of accumulation in an 
organized structure, as electricity, for example, may be accumulated under certain cir- 
cumstances, in a properly constructed machine :—whether we may speak of vital force, 
as in the case supposed, of electrical force ;—and whether the former, by accumulation, 
effects changes in a manner corresponding to what the latter is known to do. Although 
analogy is a dangerous basis for argument, yet we may venture an affirmative reply to 
the above queries. In animals, nerves convey and serve to concentrate the vital force, and 
the levers of the organic structure are thus, through the muscles, put in action. In late 
investigations by Matteucci, the force of electricity, applied as a moving power to the 
muscles of limbs, has been calculated ; and why not, in like manner, estimate the force 
of vitality? The same distinguished investigator has ascertained, by direct experiment, 
that no electric currents circulate along the nervous cords of living animals.* Admitting 
that this accumulation of vital force is possible, we may understand why certain chemical 
combinations take place only in more advanced states of an organic structure, when its 
organization is more complete. Its concentration may be required for other purposes 
than muscular action, and, if any where, would be especially so in the function of 
reproduction. 
In the discussions in this chapter, the principle here urged, with regard to vital force, 
has been assumed, as seemingly most consonant with the various operations to be 
explained ; it has appeared more satisfactory, than to refer the developements or changes 
simply to the abundance or absence of proper nutriment, as is done by many physiolo- 
gists. If the latter proves still to be a true and complete statement of the case in living 
beings, or if the force in action is some other known power, the principles adduced in 
the preceding and following pages will no less stand, although some modification may be 
required of the mode of expressing them. The whole subject is beset with difficulties, 
and it certainly becomes one venturing upon it to moye with caution. This chapter will 
hardly be perused by a reader more ready to doubt the views presented, than the author, 
when its first lines were written. The results have gradually forced themselves upon his 
mind from the developement of the various facts, which the study of the structure and 
growth of zoophytes gradually opened to view. 
* See Electrical Magazine, 1845, 490, 495, 497. 
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