CHAPTER VIII. 



ASEXUAL REPRODUCTION PLEUROCOCCUS MUCOR 

 CONJUGATION MUCOR SPIROGYRA. 



THE present chapter deals with a part of physiology 

 hitherto hardly touched on, namely, reproduction. Every 

 organism in the world is subject to a variety of risks, 

 and is constantly in danger of being destroyed: in the 

 case of the animal kingdom the preying of one animal on 

 another, and the contest among animals of the same 

 species for food are familiar, but we are apt to forget that 

 the struggle for life is quite as severe among plants. The 

 external dangers are evident enough, slugs decimate seed- 

 lings, and other and larger animals find their food among 

 plants ; while countless parasites funguses and insects 

 live on them : plants struggle with each other to get the 

 best of the light : and they have the severities of climate, 

 cold and drought, to contend with. Given the fact that 

 plants are subject to a struggle for life, reproduction at 

 once becomes of interest, for it is those species which 

 produce the best adapted offspring, in sufficient number 

 to make up for the constant destruction, that will survive. 

 So that the ways in which a plant can produce vigorous 



