ANIMAL. 



129 



tract when stimulated, very much in the same 

 way as the muscular fibre among the higher 

 animals. Moreover, the motions by which the 

 radicle constantly seeks the ground or tends 

 downwards and the plumula shoots into the 

 air, that by which some of the higher phano- 

 gamous plants twist in spirals around objects 

 near them, and by which all preserve one side 

 of their leaves towards the light, cannot be held 

 as accidental or merely mechanical acts. Seve- 

 ral genera of the confervse and tremellae even 

 exhibit such remarkable oscillatory movements 

 as have induced different naturalists and phy- 

 siologists to reckon them among the number of 

 the animals. 



With all this, however, locomotion among 

 vegetables is a very limited power contrasted 

 with the faculty among animals. These exhibit 

 all the automatical motions of vegetables, and 

 have in addition a particular system, the mus- 

 cular, superadded to their organization, by which 

 many of the most important offices of the eco- 

 nomy are performed : not only instrumental 

 in procuring the food by which they are main- 

 tained, but in putting into play the digestive 

 and respiratory apparatus by which the nutri- 

 tive juices are prepared and assimilated, and 

 finally distributed among the higher tribes to 

 every part of the body. The existence of this 

 system is in fact one of the grand characteristics 

 of the more perfect animals. By its means 

 they react upon the external world and modify 

 it according to their wants ; by its means they 

 guide their senses and enlarge the sphere of 

 their acquaintance with things beyond them- 

 selves ; by its means they impress the air with 

 the tones and articulate sounds, or execute the 

 signs by which they make known the various 

 states of their affective or moral and intellectual 

 being to one another ; finally, by its means the 

 sexes approximate, and those acts take place 

 which lead to the engenderment of new indivi- 

 duals and the continuance of species. 



The best informed among physiologists, how- 

 ever, do not confine the motions of all animals 

 to the act of the particular tissue we denominate 

 muscular. The polypes and many even of the 

 massy acalephs, to say nothing of the smaller 

 infusories, rotifers, &c. though they move 

 freely, cannot be shown to possess muscular 

 fibres in their constitution ; neither indeed can 

 any nervous system, upon which muscular 

 contractions and voluntary motion have always 

 been held dependent, be demonstrated in these 

 creatures. It is consequently probable that the 

 means by which spontaneous motion takes 

 place in these lower animals are peculiar, as 

 indeed we must acknowledge the evident mo- 

 tions which occur under many other circum- 

 stances in the world of organization to be. 



But let us now turn to the special manifesta- 

 tions of vitality of the two great classes of 

 organized beings we are engaged in examining. 

 These we shall consider in the following order, 

 which is also that we have adopted in contrast- 

 ing the manifestations of activity of unorganized 

 and oiganized beings, namely, origin or repro- 

 duction, nutrition or self-preservation, changes 



VOL. I. 



undergone during the period of existence, or 

 the ages, and death, or end. 



ORIGIN, or the acts by which species are con- 

 tinued. Vegetables and animals alike derive 

 their origin from a birth or genesis accom- 

 plished in two different modes, either without 

 the concurrence of opposite sexes, or with such 

 a concurrence. When organized beings are pro- 

 duced without the concurrence of opposite 

 sexes, the parent either divides into several 

 pieces, each of which becomes an independent 

 individual, or throws out burgeons or buds 

 from its surface, which, being detached in due 

 season exist as self-sufficing types of the spe- 

 cies. When organized beings spring from the 

 concurrence of sexes, again, two sets of organs 

 minister to the generation, the one denominated 

 male, supplying a fecundating matter, the other 

 entitled female, furnishing a germ, which sub- 

 sequently to its impregnation by the male 

 organ undergoes a series of evolutions that end 

 in the issue of an individual resembling the 

 parents, and fitted by its own acts to preserve 

 itself and to continue its kind. 



Both of these modes of reproduction are 

 common to vegetables and animals. Confervae 

 and polypi alike exhibit the first mode, almost 

 without a difference : buds or sprouts arise 

 from the surface of both ; these adhere for a time, 

 acquire a certain size, and are finally detached to 

 become independent beings. Again, the polype 

 divided into several pieces, gives origin in each 

 of these parts to distinct polypi, exactly as the 

 cuttings of vegetables take root and grow into 

 perfect trees, shrubs, &c. 



The second mode of reproduction that by 

 the concurrence of sexes, or of organs deno- 

 minated respectively male and female, is also 

 exhibited by vegetables and animaV; indiffer- 

 ently; but there are numerous circumstances 

 distinguishing this manner of reproduction in 

 the two classes of organized beings. In the 

 first place, the sexual organs do not exist from 

 the earliest period, and during the whole course 

 of the life of vegetables, as they do in animals ; 

 the sexual organs, in fact, only occur among 

 vegetables at the time of flowering, and perish 

 whenever the end of their evolution has been 

 accomplished, never serving oftener than once 

 for the generative act. The sexual organs of 

 all animals, again, that live for more than 

 a year, suffice repeatedly for their office ; and 

 if they are not required to accomplish this 

 oftener than once in the short-lived tribes, it is 

 probably from no inherent incapacity to serve 

 again, or any destruction of the organs them- 

 selves, but simply because the term of existence 

 of the organism of which they formed a part is 

 complete, they perish with the system to 

 which they belonged. 



Another grand though not an invariable dis- 

 tinction between vegetables and animals is the 

 mode in which the sexes, or sexual organs for 

 these may be taken as synonymous terms are 

 distributed among the individuals of each class. 

 Speaking generally, it may be said that the 

 sexual organs are as commonly divided be- 

 tween two individuals among animals by whom 



