GROWTH AND REPRODUCTION. 227 



productive regions of the organism is as marked as in the flower- 

 ing plant. Thus the moonwort lyBotrychiuni) and the adder's 

 tongue {Ophioglossipn) have their spore-bearing shoots standing 

 in conspicuous antithesis to the leafy portion, and a similar 

 contrast is well seen in the royal fern {Osniu?ida) and some of 

 its allies. 



In animals, the contrast in position between reproductive 

 organs and the general body is never so marked. Yet the 

 generally posterior position of the organs, their frequent close 

 association with the excretory system, their occasional rupture 

 as external sacs, must not be lost sight of. 



{b) The Contrast in the Individual Life. — Growth during 

 youth, sexual maturity at the limit of growth, the continued 

 alternation of vegetative and reproductive periods, are common- 

 places of observation which require no emphasis. If growth 

 and vegetative increase are the outcome of preponderant ana- 

 bolisni, reproduction and sexuality as their antitheses must re- 

 present the katabolic reaction from these. But anabolism and 

 katabolism are the two sides of protoplasmic life; and the major 

 rhythms of their respective preponderance of these, give the 

 familiar antitheses we have been noting. These contrasts of 

 metabolism represent the swings of the organic see-saw ; the 

 periodic contrasts correspond to alternate weightings or light- 

 enings of the two sides. Yet the contrast is less than it seems. 

 In previous chapters we have seen how growth, becoming over- 

 growth, turns into reproduction ; and how sexual reproduction, 

 dispensing with fertilisation, may degenerate till we know it no 

 longer from growth. Reproduction, moreover, is as primitive 

 as nutrition, for not only do hunger and love become indis- 

 tinguishable in that equal-sided conjugation which has been 

 curiously called " isophagy," but nutrition in turn is nothing 

 more than continual reproduction of the protoplasm. Here, 

 indeed, we have been anticipated by Hatschek, who clearly 

 states the more than verbal paradox, that all nutrition is repro- 

 duction. 



§ 7. The Contrast betweeti Asexual and Sexual Repro- 

 duction. — In plenty, the hydra buds ; in poverty, it reproduces 

 sexually. In the same way, the liverwort on the flower-pot 

 bears its pretty cryptogamic " flowers " when its exuberant 

 growth and budding have come to an end. On rich soil the 

 plant has luxuriant foliage ; but great abundance is the reverse 

 of conducive to the richest crop of flowers and fruit. Gruber, 



