March 15, 1907] 



SCIENCE 



427 



Mr. John Chalfant, of Union, Nebr., owns 

 two sows, that from a mating with the same 

 male farrowed seven and eight pigs, all of 

 which bore the seven longitudinal stripes 

 belonging to the young of the wild breeds. 

 The parents — both sire and dams — were three 

 fourths Berkshire and one fourth Poland 

 China, of pure ancestry; and were all black 

 with white points the same as the pure animals 

 of both breeds. When these fifteen striped 

 pigs were ten days old, we predicted to Mr. 

 Chalfant that they would lose their stripes 

 under three months of age, as do our wild pigs 

 (Scrofa) at Bear Creek. This proved to be 

 true. Mr. Chalfant was kind enough — at our 

 suggestion — to mate a pair from these rever- 

 sion litters; and has recently reported the 

 progeny. We quote him verbatim: 



One of the young sows that was striped has far- 

 rowed seven pigs, as follows: two black and white 

 spotted, with sandy stripes running lengthwise; 

 one black, with sandy stripes; the other five — 

 nearly black, but with solid, sandy tinge. * * • 

 Surely this must be a reversion of a long way back. 



We have here, in this one litter, near and 

 remote reversions; representing three stages, 

 viz., the spotted pigs, representing the Poland 

 China of thirty years ago; the black, with 

 sandy tinge, showing the primitive Berkshire 

 breed of sixty years; and the longitudinal, 

 sandy stripes are a wiping out of all color 

 characters accumulated during domestication. 



Agreeing with this is a statement of Mr. 

 John P. Eay, of New York, in conversation 

 with the writer. Mr. Eay originated the 

 Silver Laced Wyandotte twenty-five years ago. 

 Twenty-one years later, he purchased a first- 

 prize cock that had been bred away from his 

 own strain fifteen years. All the progeny 

 from this cock were high-scoring and uni- 

 form; but in the product of his daughters, 

 mated with the original strain, were nine pure 

 whites among a hundred chicks. 



Another exaggerated reversion occurred at 

 Bear Creek, in pure Short Horn cattle. Two 

 white calves were bom, having red ears like 

 the wild cattle of Chillingham. Their sire 

 was a red bull and a first-strain cross between 

 English and Kentucky families. Their dams 



were both of straight Kentucky strains and 

 both red. 



The patience could be overtried with in- 

 stances of similar phenomena. 



In the pig reversions there was a hybridiz- 

 ing not of color, but of chemical. The Wyan- 

 dottes were of two pure strains in the same 

 breed, and if we may judge from the reputa- 

 tion of their breeders, they were identical in 

 the spots and barrings of every feather. 



In the example of the ' wild-color ' calves, 

 the parents were identically red in color, were 

 pure registered Short Horns ; but three-quarter 

 strain hybrids. 



We can not believe that this can be ac- 

 counted for, either by ' adding to ' or by ' ab- 

 sorption ' ; and if your readers will kindly 

 allow, we will propose a solution. 



Surmising that heredity in the chromosome 

 is chemic, or enzymic, and in normal line 

 breeding this chemical is stable and repeats 

 itself, but when precipitated by a dynamic 

 reagent the recently acquired less stable he- 

 reditary compounds are thrown down, leaving 

 only the old type in many instances. In other 

 cases a new chemical arrangement is produced, 

 as in Burbank's creations and our own swine 

 hybrid monstrosities. 



Both Castle's and Davenport's explanations 

 seem logical to their examples, as neither ex- 

 periment had reached the ' breaking up ' stage, 

 wherein we appear to get precipitated rever- 

 sion. 



Castle states that ' ordinary black individ- 

 uals, while homozygous, are not pure in the 

 sense that they contain no other pigment but 

 black ' ; and if we understand him correctly, 

 red or brown lies latent. If there were only 

 color reversion, this might apply; but there 

 are also some wonderful morphological rever- 

 sions to ancestral types, that can only be in- 

 terpreted as the result of a powerful detergent 

 acting upon the later accumulations of the 

 chromosome. 



We are now experimenting with the view 

 of learning rules of hybrid stages of reversion, 

 whereby we can ' break up ' or destroy recently 

 acquired characters at will, when these late 

 characters have proven undesirable. 



Castle's * fixation ' is good, and the theory 



