§24 4. Fortpflanzungslehre. 



fikationen zu schließen, ist der Pilz ein Pyrenomycet mit Helminthossporium- 

 Fruktifikationen. Die Infektion gesunder Knollen, bzw. Pflanzen kann durch 

 Knollen kranker Pflanzen stattfinden. Bedeutend wirksamer in dieser Bezie- 

 hung sind jedoch die Triebe und Wurzeln solcher Knollen. Das Beizen von 

 Knollen blattrollkranker Kartoffelpflanzen mit Formalinbeize ist wirkungslos. 



Brahm (Berlin). 



1784) Pearl, R. and F. M. Surface, Studies on Hybrid Poultry. 



(Ann. Rept. Me. Agr. Expt. Stat. p. 84—116. 1910.) 

 This paper discusses the results of an extensive series of experiments in cros- 

 sing Barred Plyraouth Rocks and Cornish Indian Game fowls reciprocally. Data 

 are given in regard to the inheritance of a variety of morphological and 

 physiological characters in these hybrids. Particular attention is paid to the 

 phenomenon of sex -limited inheritance. Cases of such sex-limited inheritance 

 give evidence in the F l generation in regard to gametic Constitution, of a sort 

 which is usually to be obtained only in the F 2 and subsequent generations. 

 That is, such cases furnish the same kind of evidence as is presented in the 

 phenomena of segregation. Characters inherited in a sex-limited way and ac- 

 cording to Mendelian principles in the cross studied are the barred color 

 pattern; fecundity, as measured by winter egg production; shank color, and 

 beak color. The results regarding certain other characters studied are sum- 

 marily stated as follows: 



„The percentage fertility of eggs is found to be much higher when the 

 cross is made in one direction (B. P. R. q* x C. I. G. $) than in the reciprocal. 

 The hatching quality of the fertile eggs is not found to be greatly different in 

 the cross and its reciprocal. In both cases, however, the hybrid inatings gave 

 a much higher average percentage of fertile eggs hatched than did the pure 

 matings. Study of the sex ratios indicates that proportionally more males 

 were produced among the hybrid chicks than among those from pure 

 matings." 



„The mortality records show that the percentage mortality of hybrid 

 chicks from Cornish mothers was about the same as that of pure Cornish chicks, 

 similarly the percentage mortality of hybrid chicks from Barred Rock mothers 

 was about the same as that of pure bred Barred Rock chicks. The percentage 

 mortality of all chicks whether hybrid or pure from Cornish mothers was 

 some what greater than that of all chicks of corresponding matings from 

 Barred Rock mothers. The down color of the chicks is different in the F i 

 hybrids from what it is in either of the pure breeds crossed. Dominance of 

 pea comb over Single is found to be far from perfect. The F x hybrids show 

 a perfectly graded series of comb types ranging from the perfect Single to 

 the perfect pea condition. In shape of body the hybrid males are essentially 

 like the pure Cornish Indian Game males. The hybrid females are inter- 

 mediate in shape of body between the females of the two pure breeds crossed." 



Pearl (Orono). 



1785) Tandler, J. und S. Groß (I. Anat. Inst. Wien), Über den Einfluß 

 der Kastration auf den Organismus. II. Die Skopzen. 



(Arch. f. Entw. Mech. 30. [Festband für Roux.] 2. Teil. p. 236—253. Taf. XIII. 1910.) 

 Zwei Typen: hochaufgeschossene, relativ magere, anderseits fette gedunsene 

 Individuen. Regionäre Fettansammlungen gehören aber auch zur Charakteristik 

 des ersten Typus. Kennzeichnend für beide ist ferner schlaffe Haltung, schwer- 

 fälliger wackelnder Gang, apathische Bewegungen überhaupt, Genu valgum- 

 Stellung der unteren Extremität, müder Gesichtsausdruck, verursacht durch 

 Schlaffheit der bleich-gelblichen, früh faltenreichen Gesichtshaut und durch 



