33 



in the new generation is heredity. We are not in the least astonished to find 

 carrot substance reproduced from carrot seed. We are also not astonished 

 to find a table carrot produced from a carrot which is rich in sugar and not 

 a cattle carrot rich in starch. Thus the same combinations of substances are 

 transmitted which represent the characteristic peculiarities of our cultural 

 varieties. If in practical agriculture we should plant side by side both of the 

 above-named varieties of carrots we would have opportunity to observe that 

 with the appearance of a certain degree of frost, the table carrots would 

 freeze while the cattle carrots would remain uninjured. 



The susceptibility to cold of the substance of different varieties of the 

 same species is the most easily observed example of the inheritance of such 

 peculiarities as represent predisposition to disease. Each fruit grower can 

 name varieties of fruit which are injured by frost in his orchards while 

 other varieties standing nearby are not afifected or injured. The same rela- 

 tions are found among Bowers and with grain it is a universal experience 

 tliat, among the different varieties of wheat, for example, the square-heads 

 winter-kill most easily. The same variation in the resistance of dififer- 

 cnt cultural varieties is found also in relation to other cnuses of disease, as, 

 for example, overheating and drought, excess of water etc. A great deal 

 remains to be learned of the cultural varieties and their study deserves 

 greater attention than has been given to it up to the present. 



Thus cultivation has furnished us with an ornamental plant, coxcomb 

 (Cclosla ei'istafa), which has a stem with a broad, much curled vegetative 

 tip. This broad, band-like transformation of the original cylindrical stem 

 (fasciafion) has become constant in the seed. Double blossoms are retained 

 from one generation to another. Weak or one-sided formation of the sex- 

 ual organs can become an hereditary peculiarity, as, for example, in the 

 black currant or in the strawberry culture in Alten Lande near Hamburg. 



From such examples one sees v/hat far reaching differences from the 

 usual mode of development are transmissible through the seed. Each vari- 

 ation indicates a direct thrust against a previously existing peculiarity which 

 is so strong that it is able to shatter this peculiarity permanently. The 

 peculiarities of the organism possess a varying degree of stability, i. e. the 

 form of motion which they represent is often disturbed by a weak thrust, 

 while in other cases it can not be changed by the strongest attacks of the 

 surrounding factors of growth. Among the least fixed peculiarities belong 

 the colors of the blossoms, the water and sugar content and the size pro- 

 portions of the organs which can vary even in the natural habitat. Hardest 

 to alter or cause to vary are the relative' positions of the organs and the com- 

 position of the biogens, viz., the type of substance forming cabbage head or 

 of a pear tree as such, and distinguishable from that of other plants. No 

 peculiarity of an organism may be considered as indestructible but a num- 

 ber of peculiarities will be retained from generation to generation in their 

 present form because no thrust has existed up to that time of sufficient 

 strength to shake them. These peculiarities, however, which are ac- 



