39 



of other influences on the part of the vegetative factor which accumulate 

 along one line. We find in heavily fertilized nurseries, whole plots of lux- 

 uuriantly growing sweet cherries with open or hidden gum spots and in 

 forests whole tracts and healthy looking beds of conifers which show in their 

 wood-tissue the beginnings of a resinous condition. In garden cultures 

 especially, which on an average are worked with the largest quantities of 

 nitrogen, whole plantations suddenly become diseased and are abandoned 

 because the "plants will not grow." Enough cases of this kind have reached 

 me, in which individual breeders have announced that Begonias, Primula 

 sinensis fl. pL, carnations, lilies-of-the valley, cyclamen and others which at 

 other times under the same cultural methods had always been produced in 

 the greatest perfection, re-trogress from year to year and "degenerate." Sim- 

 ilar conditions may be observed in field cultures. Entire fields of potato 

 varieties which formerly gave faultless crops now easily become black 

 specked. Sugar beets grown in the soil best suited to them tend to root rot. 

 It has been observed in the root rot of beets that plants grown from trans- 

 plants became diseased especially easily, while seedlings from the best and 

 heaviest sugar beets showed almost no root rot. Cucumbers forced under 

 glass, and those grown in fields in v/et, cold years are spoiled by gummosis, 

 and the like. 



My experience in remedying such occurrences leads to the conclusion 

 that an increase of one definite line of development is concerned in 

 these cases which is usually called forth by excess of nitrogen and water. 

 Our constantly increasing intensive cultivation not infrequently leads to a 

 showy luxuriance of the plants and then to a sudden collapse, if the equaliz- 

 ing factor is not able to act in a corresponding amount. Accordingly in 

 cases of a shown great nitrogen supply, I found the use of calcium phosphate 

 to be very advantageous. 



Such one-sided lines of development will also appear necessarily in the 

 development of the seed. If it is cultivated from generation to generation 

 under the same nutritive conditions, as when first produced, definite peculiari- 

 ties of its place of growth must become hereditary through habit. Accord- 

 ing to our theory that all peculiarities of an organism represent dynamic 

 conditions and molecular vibration-groupings, the habit would necessarily 

 be explained as inertia. The law of inertia of all matter requires that it re- 

 mains exactly in the same course and at the same rate of motion. Thus the 

 organism keeps on vibrating as it has once been impelled, until some factor 

 of vegetation changes the rate of its growth or the direction. 



Practice utiHzes this circumstance in the "change of seed," that is, in the 

 use of seed from other places which have developed a definite desirable 

 peculiarity. Thus the use of Swedjsh grain by Middle-European agricul- 

 turalists has become more extensive because it is desirable to take advantage 

 of the shorter vegetative period of the northern varieties. While an 

 especially developed mealy condition is typical of English wheat, regions 

 with opposite climate conditions produce chiefly hard wheat etc. 



