140 



and extracted forms can be reproduced with much faithfulness. 

 Colored plates from books are easily reproduced upon lantern 

 slides. The exposure required is about 200 times that for an 

 extra rapid isochromatic plate. Hence no 'snap shots' can be 

 taken, but if the light is good there need be no difficulty in 

 securing good results. Development can be carried out in an 

 ordinary dark room. The solutions used are inexpensive and 

 easily prepared." 



The August (19 10) issue of the Popular Science Monthly 

 contains an article on the r61e of selection in plant breeding. 

 Another on the r61e of hybridization follows it for October. 

 Deprecating the lack of discrimination in a public, with a "repu- 

 tation for always looking for the dollar sign," the writer wonders 

 that horticultural novelties of limited use and small importance 

 are received with loud acclaim, when new agricultural productions 

 of great economic value are almost unnoted. As an example of 

 the latter class a ten per cent, increase in yield in corn might 

 be given — an increase which would add $100,000,000 yearly to 

 the wealth of the nation. 



The discussion of selection and hybridization are well illus- 

 trated with photographs — chiefly corn and tobacco. The lack 

 of proper credit mentioned above is probably due to insufficient 

 knowledge concerning these two methods ; ignorance which these 

 articles are well adapted to destroy, with regard to range in 

 variation, technique, the difficulties to be overcome, their relation 

 to the natural method of flower pollination, the evils of inbreed- 

 ing, and the interpretation of results in the newer phraseology 

 ■ — such as Mendel's law. 



Cereal cropping and soil sterilization (Science, February 10) 

 are discussed by H. L. BoUey of the North Dakota Agricultural 

 College. He mentions (i) the large yields of high quality on 

 new soils, (2) the deterioration in amount and quality that soon 

 sets in, (3) that neither the exhaustion theory nor the toxin 

 theory can satisfactorily account for the failure of such virgin soils 

 to produce the earlier characteristic yields, (4) the improvement 



