740 
DR. CARPENTER ON THE MUTUAL RELATIONS OP 
dissimilar in themselves, are both to be looked upon as modes of operation of the 
same vital force as that which is exerted in the production of the cell. And this view 
derives remarkable confirmation from the fact, that in the history of the“ zoospores” 
of the Algse we have two distinct periods, one of ciliary action, and the other of growth 
and multiplication; so lotig as the ciliary action continues, which is provided for their 
dispersion, no further vital change seems to take place in them ; but so soon as this 
ceases and they become stationaip , they begin to exercise chemico-vital transformations, 
and to grow and multiply as cells. 
These views in regard to the mutual relationship of the different kinds of vital 
force, are strikingly confirmed by the phenomena of Nervous Agency. There can be 
no reasonable doubt that the production of nerve-force in the central organs is de- 
pendent upon the development of the peculiar cells constituting the ganglionic or 
vesicular substance ; and, as already remarked, the progress of physiological inquiry 
seems to justify the belief (long since entertained and expressed by the author) that 
either cells or cell-nuclei are the agents in the origination of nerve-force at the peri- 
pheral extremities of the nerve-fibres The nerve-force thus generated is not merely 
expended in arousing mental activity on the one hand, or in exciting muscular con- 
traction on the other, but has an intimate relationship (there can be no doubt) with 
all the other manifestations of vital force which the animal organism exhibits. So 
intimate is this relationship, so obvious is the controlling and regulating action of the 
nervous system over the operations of nutrition, secretion, &c., especially in the higher 
animals, that many physiologists have regarded these actions as necessarily 
upon the exertion of nervous force. On the other hand, it has been urged with great 
plausibility by Prof. Alison and others, that since the functions of organic life in 
Animals are performed under the same essential conditions as those of Plants, and 
since the acts of formation, secretion, &c. are effected by the very same agency in 
animals as in plants, — namely, by cell-growth, — there is no valid reason for regard- 
ing them as dependent upon nervous agency; although it must be freely admitted 
that they are greatly affected by that agency, being not merely accelerated and re- 
tarded through its influence, but also altered in kind. The view here advocated will, 
it is believed, afford a definite scientific expression for all the phenomena which bear 
upon this question. For, just as electricity developed by chemical change may ope- 
rate (by its correlation with chemical affinity) in producing other chemical changes 
* There can be little douht that such is the function of the cells of the retina, which are shown, by the 
history of the development of the eye, actually to originate in the optic ganglion. The same appears to be the 
fact in regard to the cells in relation with the peripheric expansion of the auditory nerve, which originate in the 
auditory ganglion. (See Mr. H. Geat’s paper “ On the Development of the Retina and Optic Nerve, and of 
the Membranous Labyrinth and Auditory Nerve,” at p. 189 of the present volume of the Philosophical Trans- 
actions.) And it seems probable from the researches of Kolliker (Annales des Sciences Naturelles. Ser. III. 
Zool. tom. vi. p. 102), that the plexuses which appear to constitute the ultimate distribution of the sensory 
nerves in the skin, are really composed of nerve-cells, which have sent out very slender prolongations to inoscu- 
late with each other. 
