AGRICULTURAL BOTANY. 633 



parasites as brooui rape. ilotUler, etc.. where the parasitism is complete, Ijut 

 among the hemiparasites, lilie Euphrasia, lUiiuaiithus, aud Pedicularis, uitrates 

 may or may not be present. In interpreting the results he claims that the 

 obligate parasites being unable to utilize nitrates, must depend upon their host 

 plants for their nitrogen supplies, which are taken up as combined organic 

 nitrogen by the haustoria. 



The association of Pseudomonas radicicola ■with Bacillus ramosus, \Y. G. 

 Sackett (Rpt. Midi. Anid. .s'c/., 8 ilHOU), pp. 1 ',1-1 ■'>()) . — The author calls atten- 

 tion to the fact that in preparing and developing liquid cultures of tubercle- 

 forming bacteria it frequently happens that during the growth of the germs 

 there is a fermentation set up which is not typical of P. radicicola. An exam- 

 ination of the material shows quite frequently bacteria of the B. ramosus type. 



A series of investigations was undertaken to determine the antagonism which 

 exists between different soil bacteria and the germ producing the nodules of the 

 alfalfa plants. Cultures were made in which P. radicicola from alfalfa and 

 B. ramosus were employed. An examination of the four series shows that 

 where the alfalfa germs were grown in pure cultures there was always an 

 increase in their number throughout the experimentation period. Where the 

 alfalfa germs and B. ramosus were associated in the same flask, the alfalfa 

 organisms did not in a single instance show any growth, while B. ramosus did 

 grow and multiply, although in greatly reduced numbers as compared to the 

 growth in pure cultures. 



The relation of certain biological principles to plant breeding, E. M. East 

 (Connecticut State Sta. Bui. J.5S, pp. OS. figs. 6). — -This is a critical summary of 

 the most important theories and principles of variation, evolution, and heredity, 

 with especial reference to their practical bearing on the methods of breeding 

 farm crops. The bulletin is designed to give the practical breeder an introduc- 

 tion to the theoretical side of the subject. An extended discussion is given of 

 the methods and technique of plant breeding, in which the author attempts to 

 point out what appear to be the advantages and short^'omings of the different 

 methods. 



The author summarizes the present status of our knowledge regarding the 

 subject of inheritance and hybridization as follows : 



"(1) Organisms are composed of numbers of characters which are inherited 

 as units. These units are inherited by detinite laws of which Mendel's law is 

 the first to have been discovered. Since these characters are inherited as units 

 it is most reasonable to suppose that each one has been originated fully formed, 

 i. e., as a mutation. The addition of a new unit character is the only real dif- 

 ference between this mutating organism and its progenitors, and is the true and 

 only foundation for domestic improvement. 



"(2)- The object of hybridization is to shuffle and recombine these unit char- 

 acters. Hybridization, therefore, actually produces nothing new in spite of its 

 wonderful manifestations. Just as chemical units — the elements — -can be 

 (•oml)ined and recoinbined into different compounds, so can the unit characters 

 of organisms be combined and recombined by hybridization. 



"(.->) The value of the selection of fluctuations is slightly to increase or to 

 decrease the manifestations of a unit character after it has been formed by 

 nature. Selection can never produce a unit character, for there is obviously no 

 basis upon which it could w^ork." 



This bulletin will be found to be a mo.st valuable summary and statement of 

 the principles underlying plant breeding, much of the literature of which is not 

 generally available. 



Degeneration in potatoes, (i. Massee (Roij. Bot. Gard. Kew, Bui. ^[isc. 

 Inform., 1907, No. ,s, pp. 307-31], pi. 1). — The author states that in the past few 



