74 QUARTERLY JOURNAL. 



and caloric, than the principle at rest in the egg and seed. There 

 is something before evolution, something behind the curtain, which 

 to be sure we cannot see, which makes it possible for light, heat 

 and electricity to evolve the specific being. But what is still more 

 important, we cannot conceive how, even by the joint action of 

 light, caloric and all other physical agents combined, a given being 

 is just what it is — how those forces should develop from a germ 

 one specific being and not another. The early stages of all or- 

 ganic beings are so similar that it is extremely difficult to detect 

 any differences among them ; and modern observations have estab- 

 lished the fact that at one period the higher and more perfect beings 

 pass through stages during development when their organization is 

 that of some lower and inferior tribe. Now, on the principle that 

 the mere mechanical forces develop a being, and impress upon it 

 its type, or give it its characteristics, we are wholly in the dark 

 how such certain results can take place — how the chick, for ex- 

 ample, when it is in that stage where it is taking on the organiza- 

 tion of a fish, it should not go on in its development and become a 

 fish rather than a fowl. There must be, then, it appears to us, a 

 principle, call it if you please a vital principle, in organic beings 

 which holds some control over physical force, independent of it, 

 and gives such a direction to all those movements which will end 

 uniformly in the production of a specific being in j^ny given in- 

 stance. How beautifully this is illustrated in fermentation. Do 

 we see the leaven in the flour 1 No : but still it is there — we 

 know it by its workings ; every particle is moved ; it pervades the 

 whole mass ; it prepares it for the oven ; so, though we are unable 

 to see the vital principle in its simple homogeneity, we may still 

 see it in its action. Inquiries however, of this nature, we confess, 

 are on the outskirts of the boundaries of our knowledge ; they 

 are surrounded with a dim haziness or twilight, so that it is impos- 

 sible for us to separate clearly the known from the unknown. It 

 is therefore important when we push our observations into this dim 

 circle, that we mistake not on the one hand that which is only 

 probable for that which is certain, and that we continue to feel dis- 

 satisfied with our evidence so long as it is possible to push our ob- 

 servations farther. There is undoubtedly sufficient liglit already 

 evolved upon this and kindred subjects, to encourage us still to push 

 forward our investigations ; at the same time, however, we should 



