36 



lion leafy proliferations are fornied on the fruit stalk and vaseular 

 areas. The peculiar coloring and spotting of the leaves is a form of 

 indigestion, as it were, and is similar to, if not identical with, the 

 physiological disorder known as the mosaic disease common to 

 tobacco, etc. Where the soil is unusually rich in manure or fertilizers, 

 these troubles appear to be aggravated and we obtain in addition to the 

 above characteristics unusually thick stems, contorted and twisted 

 leaves, curled up leaders and petioles and abnormal growths along 

 the vascular areas. Such cases are apparently in part the result of 

 over feeding,* and, since severe and constant pruning restricts the 

 development of foliage and branches, it would also appear to be 

 responsible for multiplying and aggravating over feeding symptoms 

 by limiting the vegetative portions of the plant, thereby preventing 

 its properly caring for or digesting the absorbed food. Normal, or 

 unpruned plants, when grown under precisely the same conditions, 

 do not display such symptoms, as they are able with their profuse 

 development of foliage to properly care for the amount of plant 

 food which they absorb. 



Young suckers or sprouts seen growing on stumps of forest trees 

 often present similar characteristics to those shown by pruned tomato 

 plants. The leaves on such sprouts are frequently highly colored 

 and much contorted, since they are supplied from root systems 

 which previously supported large trees and they present all the char- 

 acteristics of over feeding. The cases just cited represent morphol- 

 ogical and physiological conditions of a pathological nature and are 

 rather exceptional. There are, however, many correlated effects due 

 to natural causes which must be regarded as beneficial to the 

 organism. 



In the singular case of mushrooms and other plants breaking 

 through thick concrete or raising flag stones, etc.: of roots splitting 

 or raising large bowlders, sometimes developing a pressure in the 

 cells equal to many atmospheres, we have a peculiar correlative effect 

 manifested in the increased osmotic properties of cells. In the same 

 manner, applying tension to plants or stretching them by weights 

 acts as a stimulus causing them to respond readily and to develop 

 mechanical tissues, and a similar development of mechanical tissues 

 is shown in certain tendrils, etc. as a result of contact stimulation. 



*There appears to exist more or less confusion in tlie symptoms cluiracteristic of 

 Mosaic disease, Oedema and over feeding. 



