ANIMAL AND VEGETABLE 157 



remain excitable for so long a time, nor could the apple 

 continue to resist decay if its stalk was unsealed and wet. 



Under the heading " Independent Muscular Activity," I 

 am told that " there are many considerations which 

 show that excitability is independent of the nervous 

 system, although in the higher animals nerves are the usual 

 medium through which the excitability is brought into 

 action. Thus plants are excitable, and they contain no 

 nerves." The italics are my own, and emphasise a state- 

 ment upon which the whole argument depends. That 

 statement also furnishes another illustration of the manner 

 in which the student may be side-tracked from the main 

 line of independent thought and research. He is told by 

 a great authority that plants have no nerves, and, accepting 

 the dictum with the respect invariably accorded to the 

 teacher, is induced to follow a false line of reasoning. 



Every plant that grows in the soil has a nervous 

 organisation. The earth is the negative terminal of 

 Nature's electrical system, as the air, in normal conditions 

 of weather, is the positive terminal ; and every tree, 

 plant, or vegetable is charged by the earth, through 

 sensory nerves, or closed circuits, extending from the roots 

 through the stem and stalks and thence to the veins 

 (nerve-fibres or fibrillse) of the leaves. These all yield a 

 negative galvanometric reaction, while those parts of the 

 leaves between the veins, as well as the flower end of all 

 vegetables and fruits, are of positive sign. Not only have 

 plants nerves, but I shall be very much surprised if they 

 are not found to possess a lower form of motor apparatus 

 as well. 



I am far from being alone in this opinion. Ainsworth 

 Davis says 



" It has been shown that the protoplasm in adjacent 

 cells may be permanently united by fine threads of the 

 same material passing through the cell-walls. For effecting 



