APPENDIX. 



KEPRODUCTION AND DEVELOPMENT. 



Reproduction in General. In all cases reproduction 

 consists, essentially, in the separation of a portion of living^ 

 matter from a parent; the separated part bearing with jt. T 

 or inheritinfl, pertain t Qr> ^ encies torcpoat^ with T" mv ? ^r 

 It jrrntifrrij t.hr lifn hint 1 1-3- nf i<- |n jrm>r In the 

 more simple cases a/^arent merely divides into two or 

 more pieces, each resembling itself except in size; these 

 then grow and repeat the process; as, for instance, in 

 the case of Amoaba (see Zoology), and our own white 

 Wood corpuscles (p. 18). Such a process may be summed 

 up in two words as discontinuous growth; the mass, instead 

 of increasing in size without segmentation, divides as it 

 grows, and so forms independent living beings. In some 

 tolerably complex multicelrSar animals we find essentially 

 the same thing; at times certain cells of the fresh- water Po- 

 lype (see Zoology) multiply by simple division in the manner 

 above described, but there is a certain concert between 

 them: they build up a tube projecting from the side of the 

 parent, a mouth-opening forms at the distal end of this, 

 tentacles sprout out around it, and only when thus com- 

 pletely built up and equipped is the young Hydra set loose 

 on its own career. How closely such a mode of multiplica- 

 tion is allied to mere growth is shown by other polypes in 

 which the young, thus formed, remain permanently attached 

 to the parent stem, so that a compound animal results. 

 This mode of reproduction (known as gemmation or bud- 

 ding) may be compared to the method in which many of 

 the ancient Greek colonies were founded; carefully organ- 

 ized and prepared at home, they were sent out with a due 



