162 PHYSIOLOGY [BoT. Absts., Vol. IX, 



ceous as well as leguminous plants. Benefit was derived by plants in a pot when the micro- 

 organism was grown in a porous cylinder placed in the center of the pot. Inoculation with 

 Azotobacter gives similar results to those obtained with the nodule organism when the latter 

 does not bring about nodule formation. — /. /. Skinner. 



1031. MacDonald, Margaret, and E. V. McCollum. The cultivation of yeast in solu- 

 tions of purified nutrients. Jour. Biol. Chem. 45: 307-311. 1921. — Experiments indicate 

 that yeast either grows in the absence of any special growth-promoting substance or that 

 it synthesizes the substance to meet its own needs. — G. B. Rigg. 



1032. Nelson, V. E., E. I. Fulmer, and Ruth Cessna. The nutritional requirements 

 of yeast. III. The synthesis of water-soluble B by yeast. Jour. Biol. Chem. 46: 77-81. 1921. 

 — Yeast can synthesize water-soluble B. — G. B. Rigg. 



1033. Pearl, Raymond. The biology of death. II. Conditions of cellular immortality. 

 Sci. Monthly 12 : 321-335. Fig. 1-6. 1921. — The work of Jacques Loeb on artificial partheno- 

 genesis, Frank R. Lillie's work on fertilization, Leo Loeb's successful cultures of somatic 

 cells and tissues outside of the body, Harrison and Burrow's improved technique in this 

 same field, and Carrel's work with adult tissue of mammals, actual growth and development 

 of new cells and new individuals in vitro secured by H. V. Wilson, Dr. and Mrs. 

 W. H. Lewis's discovery that growth takes place in tissues outside of the body in inorganic solu- 

 tions, Carrel's success in keeping cells alive longer than the normal life of these (with the promise 

 of indefinite continuation of the same), — these all lead to the conclusion that the essential 

 tissues of the metazoan body are potentially immortal. Senescence is to be regarded as an 

 attribute of the multicellular body as a whole and not a primary attribute of the physiological 

 economy of cells as such. It shows that purely cytological methods are not suitable for inves- 

 tigating causes of senescence. — L. Pace. 



1034. Pearl, Ratmond. The biology of death. Sci. Monthly 12: 444-447. 1921.— 

 This article continues the discussion of this subject, giving tables showing chances of life 

 or death of different periods, and ages of the individual, with an analysis of these data. — 

 L. Pace. 



1035. Williams, R. J. Vitamines and yeast growth. Jour. Biol. Chem. 46: 113-118. 

 1921. — Bakers' yeast and brewers' yeast were used. The growth of each is stimulated more 

 by its own extract than by that of the other. This is interpreted to mean that there is some 

 specificity in growth stimulants, but not necessarily 2 totally different substances stimulating 

 the growth of the 2 varieties. Some results present the possibility that the antiscorbutic 

 vitamine, as a secondary factor, may stimulate yeast growth. — G. B. Rigg. 



GROWTH, DEVELOPMENT, REPRODUCTION 



1036. Brannon, J. M. A simple method for growing plants. Amer. Jour. Bot. 8: 176-178. 

 Fig. 1. 1921. — The author has grown plants successfully when completely immersed in 

 sterilized and sealed culture solutions containing sugar and mineral salts. Flax, alfalfa, 

 corn, peas, and timothy may be readily grown iU this way and thrive better than in agar 

 or in the ordinary water culture. The author points out the particular advantage of this 

 method when plants are to be grown in the dark. — E. W . Sinnott. 



1037. Harris, J. A., and H. S. Reed. Inter-periodic correlation in the analysis of growth. 

 Biol. Bull. [Woods Hole] 40: 243-258. 2 fig. 1921.— From a series of data collected by one of 

 the authors the attempt is made to illustrate the application of inter-periodic correlation 

 coefficients to the problem of growth. In the discussion the following terms are used 

 and defined. Growth stage is the time at whicli a series of organisms is measured. 

 Growth period is the time elapsing between the sth and the s+nth growth stage, and the 

 growth increment is the increase in size during such period. The relative growth increment 



