Varietäten, Descendenz, Hybriden. 647 



of this phenomenon in Egyptian cotton is afforded by the Nubari 

 and the Yuma varieties. 



If the tendency to produce mutants is a result ot remote or 

 complex hybridization, the mutability of Egyptian colton might be 

 accounted for upon either of the following grounds: 1) The supposed 

 hybrid origin of the type as a whole, or 2) later crossmg with 



other types of cotton. ■ u u 



Ever since mutation became recognized as a factor m the Dree- 

 ding of Egyptian cotton the following methods have been followed 

 in Arizona: 1) Recognition and isolation of desirable mutants; 

 2^ selection and comparison on the progeny-row basis of those 

 individuals among their progeny which express most fuUy the 

 desirable characters of the new type; 3) elimmation from the 

 seed-increase fields, preferably before blossommg begins, ot the 

 aberrant and otherwise undesirable individuals. ^ , „ 



The plates illustrate the habit, leaves, involucres and bolls ot 

 the different varieties (Pirna, Gila, Mit Afifi. Yuma). Jongmans. 



Pearl, R., Some recent studies on Variation and corre- 

 lation in agricultural plants. (American Naturahst. XLV. 

 p. 415-425. 1911.) 



This paper contains a review of the most important papers on 

 biometric analysis of studies on Variation published mostly in the 

 year 1910. It is evident that biometrical methods are rapidly gai- 

 ning a place among the agricultural investigator's working tools. 

 The agricultural investigator has an almost unique opportunity to 

 make 'significant and profitable application of biometric methods of 

 research. Jongmans. 



Redfield, R. L.. Acquired characters defined. (American 

 Naturalist. XLV. p. 571—573. 1911.) 



There are three ways in which an individual obtains characters. 

 Some characters are born in the individual, some are acquired, and 

 some, such as mutilations, are thrust upon him. 



Acquired characters are not new characters, but characters 

 which are changed from their normal inborn condition by their 

 own functional activity, and are to be clearly distinguished from 

 characters thrust upon a passive individual. 



It has been demonstrated beyond all question that those charac- 

 ters which are thrust upon the individual, such as mutilations, are not 

 inherited, But we want some clear and precise evidence in regard 

 to the inheritance of those characters which are acquired, such as 

 physical or mental strength, and can by no possibility be thrust 

 upon the individual. Jongmans. 



Shaw, J. K., A System of recording Mendelian observations. 

 (American Naturalist. XLV. p. 701—704. 3 Fig. 1911.) 



In connection with some investigations in plant breeding at the 

 Massachusetts Experiment Station a System of records has been de- 

 vised for use in experiments where segregation of characters occurs 

 that has worked very well in practise and m.ay be found suggestive 

 to other observers who are investigating Mendelism and handling 

 a considerable number of plants. 



