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hope, perhaps, of bearing seed, and scattering it before the greedy 

 insects had sapped the very foundation of life. 



Perhaps the greatest difficulties which the vegetable constitu- 

 tion had to struggle against were those which arose from improper 

 or insufficient food. An oak tree grown in a bottle flourished 

 vigorously for a few seasons till the time came when spoon-diet 

 must be thrown aside and strong meat must be provided. Oxygen 

 and hydrogen, carbon and nitrogen, wei-e all present in its air and 

 water, but the growing tree required more substantial food, silex 

 and lime, phosphorus and iron ; and, if these were not provided, it 

 was interesting to observe how, for dear life, the little tree gave up 

 all hope of making " heart of oak," and resigned itself to the life of 

 an invalid, building soft branches and unnaturally large leaves to 

 make up in starch and gluten for its other deficiencies. The 

 struggle for life in plants was a long protracted one. If we turned 

 over with the spade a piece of earth covered with shepherd's purse 

 and knot grass, so as to bring the roots upwards, there was sure to 

 be one branch that was bent so as to point upwards, and this 

 particular branch took upon itself the functions of a main stem, 

 deriving its nourishment from the remainder of the plant until 

 some of the root fibres could come into play again. He had seen in 

 Australia large trees lying on the ground in a state of decay save 

 one branch, which had fallen upright and was now developing into 

 a new tree, and he believed he spoke the result of others experience 

 as well as his own when he said that there were no flowei-ing plants 

 or trees which might not, under certain circumstances, become, at 

 least temporarily, parasites. Everybody must be familiar with that 

 flaccid, sodden state which plants assumed when deprived for a time 

 of water ; but it might have escaped the observation of many that 

 the same state was sometimes seen in plants which were well 

 watered, either artificially or by rain. He had frequently 

 noticed this in the common chickweed, which, from growing 

 on roadsides, is much exposed to heat, and he was inclined 

 to regard it as a disease produced by excessive evaporation. 

 The settlement of dust on wet leaves, by stopping healthy 

 transpiration, often caused diseases which affected the whole 

 plant, and those who had amused themselves, as he had done, 

 by painting leaves with varnish and supplying them copiously with 

 water, would have remarked how long it was before the plant 



