Physiology of Plants. 69 



Chapter VII. 

 Physiology of Plants. 



Empirical Stage Influence jrom Animal Physiology Nutrition in 

 Plants Movement and Feeling in Plants Sachs Reproduction in 

 Plants Ancient Conjectures as to Sexuality of Plants Camerarius 

 Kcelreuter Sprengel The Act of Fertilization Sexuality of 

 Cryptogams Experiments on Sex and Reproduction. 



The lore of the gardener embodied from ancient times 

 not a little knowledge which we would now call physio- 

 logical, but it was long in acquiring scientific Empirical 

 value. It is impossible to believe that the stage. 

 old practice of caprification (concerned with the pollin- 

 ation of the fig), or the equally ancient device of dusting 

 the female date-flowers with pollen, were in any real 

 sense understood ; and the same must be said of simpler 

 matters, such as pruning and manuring. The old lore 

 was empirical and not scientifically understood. 



Just as discoveries as to the functions of the human 

 body raised inquiry in regard to the functions of animals, 

 so the facts of animal physiology have from Influence 

 time to time prompted the botanists to look from Animal 

 for similar phenomena in plants. Thus Har- Ph y siol y- 

 vey's discovery of the circulation of the blood raised the 

 question as to the movements of the sap. On the whole, 

 it must be confessed that vegetable physiology has 

 always lagged behind animal physiology, and this is not 

 unnatural, since there is much less division of labour in 

 the plant than in most animals, and the analogy of the 

 human body, always suggestive to the animal physiolo- 

 gist, is hardly relevant. 



There are few more striking examples of the slow and 

 often devious progress of science than the history of the 

 physiology of nutrition in plants. The de- Nutrition in 

 tails are skilfully set forth in Sachs's History Plants. 

 of Botany, on which the following summary is based. 



The Aristotelian theory that the food of the plant is 

 prepared for it in the ground seems now crude enough, 



