164 Varietäten, Descendenz, Hybriden. — Physiologie. 



Shull, G. H., The genotypes of maize. (Amer. Nat. XLV. p. 

 234—252. 1911.) 



Evidence is given that as the result of comparison between 

 cross-bred and self-fertilized strains of Indian com, that there are 

 many genotypes which although they cannot always be distinguished 

 by definable external characters, can be proved to be just as cer- 

 tainty discrete as the types whose distinguishing features can be 

 recognized as Mendelian unit characters. Furthermore the seif ferti- 

 lized families derived originally from a common stock, do differ by 

 morphological characteristics and there comes to be a great unifor- 

 mity in regard to the presence of these characteristics in all the 

 individuals of a given seif fertilized family. As the result of experi- 

 ment it is shown that a normally cross-bred plant like Indian com 

 harmonizes in its fundamental nature with such normally self-ferti- 

 lized material as beans and wheat and such colonial varieties as 

 potatoes, paramecium, etc. that the egg-cells and sperm-cells of even 

 the most complex hybrids present a limited number of different 

 types which can be assorted into homozygous combinations, and 

 that therefore the progressive change resulting from continued 

 selection may be simply explained as the gradual segregation of 

 homozygous types or of the most efficient heterozygous combinations. 



Moore. 



Aisberg, C. L., Mechanisms of cell activity. (Science. II. 

 XXXIV. p. 97— 105. July 1911.) 



A general discussion of the subject with the conclusion that 

 organic chemistry alone cannot throw much light on the mechanism 

 of protoplasm. These mechanisms are dependent upon structure and 

 this organic chemistry is not capable of revealing. The mechanisms 

 are themselves interrelated and coordinated. These relations and 

 coordinations are not capable of stud}'' by the usual analytical 

 methods. The process of analysis destroys them as it destroys life 

 itself of which they are most characteristic manifestations. These 

 characteristics of life can be approached only from the basis of 

 structure of some sort. For a proper understanding of it, anatomical, 

 chemical and physical knowledge must be combined. The resultant 

 alone offers the hope of widening our knowledge of the mechanisms 

 of cell activity. Moore. 



Appleman, C. O., Physiological behavior ofenzymes and 

 carbohydrate transformations in after-ripening ofthe 

 potato tuber. (Bot. Gaz. LH. p. 306—315. Oct. 1911.) 



The method recommended by Grüss for determining the rate 

 of peroxidase activit} r in the potato tuber gives no indication of 

 the rate of activity in the conditions approaching those of the living 

 tuber. This is due to errors introduced by inclusion of the peroxi- 

 dase in the clot of coagulable proteins and to the loss of peroxi- 

 dase during the process of drying the slices. After a few days 

 the Peroxydase is practically destroyed in the dry powdered potato. 

 This method always showed an apparent increase in Peroxydase 

 activity in cold storage potatoes. The evidence at hand seems to 

 indicate that this is due to an alteration of coaguable proteins by 

 low temperature, thus modifying the amount of peroxidase occluded 

 by the clot. 



