262 Vererbung, Variation, Mutation. 



In 1849 Brahma cattle were brought to the United States and their offspring- 

 distributed throughout the Southwest. It is also possible that Brahman blood was 

 brought in by the way of Mexico from cattle imported from Spain. Subsequent 

 cross breeding with non-resistant breeds of cattle probably accounts for the eli- 

 mination of these resistant characters and for the present difficulty in raising 

 cattle on the tick infested ranges and pastures. Experiments have been recently 

 tried in again introducing Brahma cattle into the herds in Texas with remarkable 

 success. Whenever Brahma cattle are crossed on pure or grade Herefords, the 

 color and other characters of the latter are, on the whole, dominant in the T^ 

 generation and when the cross is on grade or pure Durham, the characters of 

 these are dominant in the F^ progeny. When Brahmas are crossed with native 

 "Texas cattle" the resulting Fj progeny, in some cases, resemble mostly the 

 Brahma parent, but this is probably due to the fact that the native cattle al- 

 ready possess Brahman characters from the earlier introduction of these cattle. 

 It is not altogether clear at present that segregation is in a simple Mendelian 

 1:2:1 ratio. The hybrids from crossing Brahman bulls on pure or high grade 

 Hereford or Durham crosses give offspring that average, under the same living 

 conditions, 50 percent or more larger than the Hereford, Durham, or native 

 cattle. The bulls are more prolific. At present the records are not complete but 

 it is probable that the peculiar horns, dewlap and sheath, drooping ears, large 

 hump and color of the Brahma may be unit characters. All indications point 

 strongly to the fact that with the introduction of the Brahma cattle immunity 

 to the cattle tick is introduced, since in these regions the cattle tick seems to 

 have been completely eradicated. Pearl (Orono). 



822) Sturtevant, A. H. (Columbia University), The Himalayan rabbit case 

 with some considerations on multiple allelomorphs. In: Amer. Natural. 

 Bd. 47, S. 234 — 238, 1913. 



It has been shown by Castle, Hurst and P u n n e 1 1 that the Himalayan pattern 

 in rabbits is a simple recessive to seif colour and a simple dominant to albino, 

 and yet seif X albino never produces any Himalayans. Other cases of similar 

 triple allelomorphs have been found by Shull in Lijclmis by Emerson in beans, 

 by Baur in Äquilcgia, and by Morgan in the fly Drosophüa. It is pointed out 

 that in all these cases the presence-absence hypothesis, involving the dropping 

 out or addition of whole '"genes", offers a less simple explanation than the con- 

 ception of a relatively unstable "gene" which may undergo various modifications 

 which are in some cases reversible. Gates (London). 



823) Cook, 0. F. (Washington D. C), Mendelism and interspecific hybrids. 

 In: Amer. Natural, Bd. 47, S. 239—245, 1913. 



A criticism of a paper by Nabours in which the alternative inheritance in 

 crosses between Durham and Brahma cattle is described as Mendelian. The writer 

 considers that alternative expression of characters in hybrids is not evidence of 

 their alternative transmission, and finds that in interspecific hybrids cohereuce 

 of the various parental characters is the most striking result. 



Gates (London). 



824) Newmsiil, H. H. (Chicago, University), Five generations of congeni- 

 tal stationary Nightblindness in an American family. In: Journal of 

 Genetics, Bd. III, Nr. I, S. 25— 38, 1913. 



Gives a füll pedigree of a family showing nightblindness, with details of 

 all the members about whom anything is known. The disease is transmitted 



