368 LITERARY AND SCIENTIFIC. 



power inherent in all of them of regenerating mutilated parts, which, as he after- 

 wards explained by reference to the experiments of Blumenbach, is in a direct ratio 

 to the simplicity of their construction. This power, connected with that of nutrition, 

 he observed, afford decided evidence of the superiority of the machines con- 

 structed by the Creator over the most perfect productions of modern art. 



The lecturer then showed the distinctive differences between the vegetable and 

 animal kingdoms, which latter had formerly been defrauded of many of its 

 subjects, having been considered as marine plants, until the experiments of 

 Trembley and others proved their animality. He then commented on the Linnaean 

 aphorism. This aphorism he asserted to be inefficient, since there is no proof that 

 those simple animals in which no traces of nerves can be found, present any traces 

 of sensibility. For this term he proposed to substitute irritability, and although it 

 might appear that this power was possessed by certain vegetables, yet on examination 

 it would be found that the phenomena displayed by them are entirely different 

 from the irritability of animals : — an assertion which he illustrated by referring to 

 the experiments of Lindsay,. Dutrochet, and Mayo, on the motion of the leaves of 

 the Mimosa pudica, or sensitive plant, showing it to be dependent on the 

 expansive power of the lobular bodies at the base of the leaf stalk, leaf, &c. whilst 

 the motions of animals are caused by contraction. 



The lecturer next proceeded to describe the phenomena of life, which is only to 

 be known by its effects : — " of the essence of life," he said, "we are utterly igno- 

 rant, we know if only as the connecting bond which unites and keeps in action a 

 certain assemblage of functions in an organized body. On no other subject 

 have such absurd and groundless theories been formed — volumes have been written 

 in support of particular hypotheses, but none are sufficient to account for all that is 

 in relation with life, but that which ascribes its origin to the voice of omnipotence, 

 and its continuance and preservation to the same Almighty power." The example 

 by which Cuvier illustrates the presence and absence of life is exceedingly beautiful. 

 " Picture to yourselves, he says, a female in all the vigour of youth, and all the 

 might and majesty of loveliness, nameless charms shine around her — 



The light of love, the purity of grace. 



The mind, the music breathing from her face. 



The heart whose softness harmonized the whole. 



In a moment, without apparent cause, she ceases to breathe, all power of motion 

 has vanished, and now contrast what follows with that upon which a few moments 

 since we gazed with admiration and delight. The cold and senseless mass is no 

 longer affected by surrounding objects ; the beautiful regularity and symmetry of 

 form begins to alter ; the relaxed and flaccid muscles allow the bones to project 

 from beneath ; the eye " that fires not, wins not, weeps not now," becomes 

 glassy, flaccid, and opaque;" but these, observed the lecturer, are only the 

 precursors of changes, into the particulars of which he should not enter. Thus 

 strangely was life constituted ; but it was animated in the human being by an 

 immortal spirit, of which all that could be said was — that it was placed there by 

 the great Creator. 



His definition of a species we give at length. *' I have already mentioned, that a 

 fixed external form belongs to each animal, and that it is continued from parent 

 to offspring. This has been the case from time immemorial. AH the animals 

 belonging to one of these forms constitute a species. This resemblance is not to 

 be taken in a rigorous sense, for every being has its individual characters, so that 

 a shepherd can distinguish every sheep in his flock. Proceeding then on the 

 criterion of definite form, we may define a species as a collection of all the 

 ijidividtcals which have descended one from the other, or from common parents, 

 and of all those which resemble them as much as they resemble each other. This, 

 then, is the first step ; next we unite together those most nearly resembling each 

 other so as to form genera. These again are grouped into orders, next into 

 classes, and finally into departments." 



The lecturer observed that he had taken the system of Cuvier as his text, 

 though with some alteration, for instead of commencing with man, and pro- 

 ceeding downwards [to the infusoria, > he had considered it more philosophical to 

 begin with the lowest orders of organic life, and thus by a progressive development 



