Wilsdorf: German Zootechny 



115 



Furthcnnorc, he points out, "it is 

 by no means assured that all characters 

 JMcndehze." On the whole, he con- 

 siders MendcHsm an instrument of 

 great future promise, but ont which is 

 hardly likely to be of much value to the 

 practical breeder at the present day. 



Telegony and maternal impressions 

 are mentioned as supposed factors to 

 which many breeders ascribe unexpected 

 variation. As Dr. Wilsdorf says, these 

 can no longer be considered anything 

 but superstitions, yet they are still 

 widely held. "In East Friesland, the 

 Eldorado of the German cattle industry, 

 many breeders still believe heart and 

 soul in the power of maternal impres- 

 sions on the cow. If a red or red-and- 

 white calf is bom in a herd of solid 

 black-and-white color, the mother 

 must have looked at some red object. 

 You can argue as much as you like, 

 this explanation can not be shaken in 

 East Friesland. And yet the true 

 explanation lies right under their noses ! 

 either the neighbor's herd is red-and- 

 white, and one of his bulls has jumped 

 the fence, or else it is a case of atavism 

 such as I have already spoken of. A 

 belief in maternal impression, like a 

 belief in telegony, is a superstition with 

 which no serious breeder will waste 

 time; but it cannot be easily eradicated 

 from the minds of the great mass of 

 farmers, because it has sunk in so 

 deeply." 



A proposition which extremists some- 

 times class with the foregoing, but for 

 which Dr. Wilsdorf shows more toler- 

 ance, is the belief in the inheritance of 

 acquired characters. Stockmen, par- 

 ticularly in regions where breeding has 

 been the occupation of the same family 

 through many generations, have amassed 

 rich stores of experience which satisfy 

 them that animals under the influence 

 of better care, feeding and housing 

 change their form and characteristics, 

 and that these changes occurring in the 

 life of the individual are inherited by 

 their progeny. This conclusion, which 



^This is denied by C. B. Davenport, "Skin Color of Mulattoes,"JouRN.A.L of Heredity, V, 12, 55.S, 

 December, 1914. The color seems to be due to numerous separate factors which act as units in 

 inheritance. Dr. Wilsdorf might better have mentioned height as a character which shows 

 blending; although in this case too the blending is very likely due merely to the fact that the unit 

 characters involved are too many and too small to permit the observer to see their segregation. 

 — The Editor. 



"The second method of heredity is 

 the blending. In it the characters fuse 

 together so that the product stands 

 half way between the two parents. 

 The midattoes resulting from crosses 

 between negroes and whites may be 

 cited in this connection: their color is 

 constant in succeeding generations.^ 



' ' In mutational heredity a form 

 appears in the first generation which 

 was not present in either of the parents. 

 As an example genetic literature usually 

 cites Bateson's cross of fowls with rose 

 comb and fowls with pea comb; the 

 offspring had a walnut comb — that is, 

 an entirely new form; which however, 

 could not be bred pure in succeeding 

 generations, but segregated in the 

 second generation, in the following 

 proportions: 9 offspring had a walnut 

 comb, 3 a rose comb, 3 a pea comb and 

 1 a single comb." 



THE VALUE OF MENDELISM. 



More important than these to the 

 breeder of live-stock is the fourth 

 method, Mendelism, Dr. Wilsdorf says, 

 but after he has explained it at some 

 length, he feels obliged to conclude: 



"Now if we ask ourselves what 

 importance Mendelism has for prac- 

 tical animal breeding, we must admit 

 at the very outset that the develop- 

 ment of the rule is still too new to 

 admit of sure conclusions. In this day 

 no one is likely to deny that a thorough 

 knowledge of this rule, which solves so 

 many problems that before its discovery 

 were absolute mysteries, is of the first 

 importance. In agricultural animal 

 breeding, however, we are confronted 

 by one almost insuperable difficulty — 

 that our most important domesticated 

 animals bring only one offspring into 

 the world at a time; whence the con- 

 ditions of heredity are naturally not 

 easy to observe. It is only with such 

 animals as swine, which produce larger 

 numbers of young at a time, that one 

 can derive much immediate help from 

 Mendel's Rule." 



