608 



SCIENCE. 



[N. S. Vol. XV. No. 381. 



other fungi. Cornu published an interesting- 

 paper on the grape mildew (Peronospora) . 

 Nawasehin has increased our knowledge of 

 the parasite which causes club root in 

 cabbage. "Went and Beyerinck have pub- 

 lished a number of very suggestive papers 

 on enzymes. As already stated, this list 

 is not designed to be complete. It might 

 be greatly extended. 



A great advance has also been made in 

 treatments for the prevention of disease. 

 In France, Millardet saw that the mildew 

 did not attack certain grape vines which 

 had been sprinkled with a mixture of blue- 

 stone and lime to prevent thefts of the grape 

 bunches. He had the alertness of mind to 

 recognize that here was the germ of an im- 

 portant method of treatment, and, Avith the 

 help of Gayon, promptly elaborated it for 

 the prevention of mildew of the grape. Fol- 

 lowing fast on the heels of this discovery 

 was its application in France, Italy and 

 the United States for the prevention of 

 other fungus diseases. By the General 

 Government, under the energetic direction 

 of Scribner, and subsequently of Galloway, 

 and a little later by many experiment sta- 

 tion workers and farmers, this and similar 

 methods of treatment were applied success- 

 fully in the United States for the preven- 

 tion of the black rot of the grape, leaf spot 

 of the pear, apple scab, and a number of 

 other serious diseases of plants. At one 

 time this treatment was hailed as a general 

 panacea for all plant diseases. In Den- 

 mark, Jensen discovered that smut of 

 various grains could be prevented by soak- 

 ing the seed in hot water for a few minutes. 

 These experiments were subsequently re- 

 peated, expanded and confirmed in this 

 country by Kellerman and Swingle. Thax- 

 ter and Sturgis demonstrated that onion 

 smut was only communicable during the 

 seedling stage of growth and that, if plants 

 were grown for a few weeks in healthy soil, 

 they might be transplanted to fields badly 



infested with this smut without danger of 

 infection. BoUey showed that the potato 

 scab was frequently disseminated by seed 

 potatoes, and in such cases could be con- 

 trolled very satisfactorily by soaking the 

 infected seed potatoes in a solution of cor- 

 rosive sublimate. This treament is, how- 

 ever, not successful in case the fungus is 

 already present in the soil. Coquilette, 

 the entomologist, demonstrated that cer- 

 tain scales infesting orange trees in Cali- 

 fornia could be controlled by fumigating 

 with hydrocyanic acid gas, and "Woods and 

 Dorsett in Washington subsequently ex- 

 tended this treatment and applied it on a 

 large scale, most successfully, for the free- 

 ing of hot-house plants from scale insects 

 and aphides. This treatment has subse- 

 quently been pretty generally applied in 

 the United States for the fumigation of 

 nursery stock. Riley and others con- 

 ceived the idea that the best method of eon- 

 trolling certain scales would be by multi- 

 plying their insect parasites, and the 

 threatened destruction of the orange 

 orchards of California by the cottony cush- 

 ion scale was avoided in this way, viz., by 

 the introduction of a lady-beetle from 

 Australia. Giard, Snow, Forbes and 

 others have experimented with certain 

 fungous parasites of crop -destroying in- 

 sects, hoping to spread epidemics among 

 them, but thus far with only par- 

 tial success. The dreaded San Jose 

 scale can now be held in check in this coun- 

 try by iusecticidal sprays. Potter, Hal- 

 sted and others have sho\\Ti that club root 

 of cabbage may be partially prevented by 

 heavy liming of soils. Millardet, as a 

 result of thousands of crosses of Vitis 

 vinifera with hardy American species, has 

 obtained wine grapes resistant to Phyllox- 

 era. Pierce, by similar methods, has ob- 

 tained a raisin grape resistant to coulure. 

 Quite recently the Dutch in Java have 

 largely circumvented the Sereh disease of 



