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SCIENCE 



[N. S. Vol. XL. No. 1039 



respiratory enzymes, and the others have proved 

 out of accord with known facts. The hypothesis 

 that loss of viability is due to a slow coagulation 

 of cell proteins of the embryo has been proposed 

 and is being tested out by the writers. The test- 

 ing of this hypothesis is carried out by getting the 

 life duration at any two high temperatures and 

 using these values in the formula that expresses 

 the relation between time and temperature for the 

 coagulation of proteins to find the life duration 

 at any desired temperature. As an illustration of 

 the results, a variety of wheat with 12.5 per cent, 

 moisture gives a calculated longevity of 9.8 years 

 at 20° C. and 110 years at 0° C. This and other 

 calculated values at 20° C. tallies rather closely 

 with records of longevity in wheat. Also the cal- 

 culated values at various high temperatures tallies 

 rather closely with the found life duration at 

 those temperatures. Two points of technique de- 

 serve special mention, the method of maintaining 

 the constant high temperature and the method of 

 sterilizing the seeds for germination. If the hy- 

 pothesis and method prove tenable they will be of 

 great economic significance in making possible a 

 quantitative statement of longevity as influenced 

 by the factors of moisture content and tempera- 

 ture. 



Edwin O. Jordan: Variation in Bacteria. 



An attempt is made to distinguish in specific 

 eases between true mutations and the more or less 

 permanent adaptive modifications evoked in bac- 

 teria by definite environmental stimuli, and to 

 determine the relative value of each in the forma- 

 tion of so-called bacterial species and varieties. 

 The effect of acclimatization upon bacteria is 

 considered as part of the problem. Specific in- 

 stances of the extent of variation in a given 

 direction and of the plasticity of a pure line 

 strain are also brought out. 



William Trelease : Phoradendron. 



Outline of a taxonomic revision of this genus 

 of American mistletoes, with indication of a new 

 basis for its primary subdivison. The paper em- 

 bodies the results of a study of all of the ma- 

 terials in the principal American and European 

 herbaria in the course of which almost all of the 

 species have been photographed from the types. 

 One fourth of the recognized species belong to a 

 section that is found in the United States, Mexico 

 and Central America, but is absent from the West 

 Indies and South America; and three fourths, to 

 a section that extends through South America and 

 the West Indies and through Central America and 



southern Mexico, but is entirely absent from the 

 United States. 



Though apparently well adapted to dissemina- 

 tion by birds, the species are rarely of wide 

 geographic range and in general are confined to 

 areas limited by barriers which are effective for 

 non-parasitic plants. 



VII. Zoology and Paleontology 

 C. M. Child: A Dynamic Conception of the Or- 

 ganic Individual. 



Organic individuation may be either radiate or 

 axiate. An organic radius or axis in its simplest 

 terms is dynamically a gradient in rate of meta- 

 bolism or of certain fundamental reactions. In 

 this gradient the region of highest rate of reac- 

 tion is in greater or less degree dominant over 

 other regions because of its higher rate of reac- 

 tion and therefore infiuences the dynamic pro- 

 cesses in them and determines the orderly course 

 of development and functional relation. This 

 dominance apparently depends primarily rather 

 upon transmitted dynamic changes than upon 

 transported chemical substances and the integrat- 

 ing action of the nervous system is its final ex- 

 pression. Since a decrement occurs in transmis- 

 sion, dominance becomes ineffective beyond a 

 certain variable distance and the size of the 

 individual is therefore physiologically limited. 

 Eeproduction results from the following condi- 

 tions: first, physiological or physical isolation of 

 a part from the influence of the dominant region; 

 second, a greater or less degree of dedifferentia- 

 tion or loss of its characteristics as a part in 

 consequence of the isolation; third, the presence 

 or establishment in the isolated mass of an axial 

 gradient or gradients; fourth, a new individuation 

 and developmental history in consequence of the 

 presence of the gradient and a dominant region. 

 The axial gradients are not fundamental proper- 

 ties of protoplasm but result from local differences 

 in the action of factors external to the proto- 

 plasm, cell, or cell mass in question. Orderly 

 progressive development and definitely coordinated 

 function are impossible except where such gradi- 

 ents exist or have existed. 



Frank E. Lillie: The Fertilising Power of 

 Sperm Dilutions. 



On the basis of the usual supposition that a 

 single active spermatozoon may fertilize an egg 

 of its own species, fertilization of eggs in series 

 of sperm suspensions of increasing dilution should 

 run in accord with the following law : To the point 

 in the series in which each egg receives a single 

 spermatozoon all of the eggs should be fertilized; 



