NOTES AND ABSTRACTS. 



493 



Hot Water as an Insecticide. By G. Eoillet (Le Jard., vol. 

 xxiii., No. 548, p. 380; Dec. 20, 1909). — All apLides and caterpillars 

 are killed by immersion in water heated to 45<^ C, and beetles and other 

 insects invested with a chitinous covering perish in water of 50^ 0., 

 whereas plants will survive immersion up to 54° 0. Nothing, accord- 

 ingly, is simpler when pot plants are attacked by insects than to roll 

 the pot m a cloth so that the soil does not drop out, then plunge it into 

 water at 60^ 0. and shake it in the water for half a minute. On trees, 

 again, the msects may be destroyed by applying hot water with a paint- 

 brash or by s}irayiiig the trees, and in the latter case it must be remem- 

 bered that the water loses heat in passing through the air, so that if the 

 jet is two yards the tree the water should be at 55°, if four to six 

 yards off, at 60° to 65°, and so on. In view of the highly deleterious 

 nature of many insecticides, it seems as though the method might 

 be practised with advantage. The only difficulty is the exact regulation 

 of the temperature, which; however, can be easily surmounted. 



F. A, W. 



Hymenomycetes {Beih. Bot. Cent. xxvi. 2. Abt. Heft ii. pp. 205- 

 225; 1910). — M. Britzelmayr (^Augsburg), gives a revision of his 

 diagnoses of Boletus, Polyporus, &c... as far as Typhiila and Tremella. 



G. F. S.-E. 



Indian Corn, Breeding of. By Louie H. Smith {U.S.A. 

 Exy. Stn, Illinois, Bull. 128; 1908). — The author records the results 

 of the selection experiments carried on at this station from 1897 to 

 1906. 



The paper is of very great importance to all breeders of plants, and 

 is of great interest also in the theory of heredity. A large number of 

 experiments were made in carefully selected plots and every precaution 

 was taken against accidental crossing. 



The intention was to produce by continuous selection four races of 

 Indian corn, characterized by (1) a high percentage of protein (there- 

 fore more valuable as feeding stuff), (2) a low percentage of protein 

 (for manufacturers of glucose, gum, &c.), (3) a high percentage of oil 

 (commercially valuable), (4) a low percentage of oil (important for 

 swine-feeding). 



As regards (1) the high protein race, the author began (in 1896) 

 by selecting individual seeds with a high percentage of protein (12*54 

 per cent.) from a crop averaging 10*92 per cent, protein. 



In 1906 the seed selected had a percentage 16*30, and the average 

 i of the crop had risen to 14*26 per cent, of protein. The average had 

 therefore been raised from 10*92 to 14*26. In the tables recorded at 

 the end of the volume we notice that individual seeds were found with 

 j even 17*67 per cent, protein. 



In race (2), bred for a low percentage of protein, the results are 

 almost equally striking. Beginning in 1897 with seeds of 8*96 per cent. , 

 j selected from a crop averaging 10'92 per cent., the seeds in 1906 had 



VOL. XXXVI. K K 



