138 



SCIENCE, 



[N. S. Vol. IV. No. 83. 



should be discarded as seed, 

 tliis trouble is not given. 



The cause of 



EAKLY AND LATE POTATO BLIGHTS. 



Bulletin 113 of the Cornell, N. Y., Sta- 

 tion treats only of the diseases of the 

 potato, giving several illustrations of these 

 troubles and one coloritype plate of blight. 

 Two leaves are shown in this, one of the 

 ' early Blight ' and the other of the ' late 

 blight." The former is due to the fungus 

 Macrosporium Solani, E. & M., and the latter 

 to Fhytophthora infestans, DeBy, a downy 

 mildew which, when affecting the tubers, 

 produces the potato rot, an old enemy in 

 Europe, where it has caused famines, as in 

 Ireland in 1846. Prof. Lodeman draws 

 largely upon the literature of this blight, 

 mentioning its rapid growth in and destruc- 

 tion of the attacked vines and the disagree- 

 able odor of the ruined potatoes. The 

 germ tube from the spore secretes a ferment 

 that dissolves the cell wall of the host, and 

 permits the parasite to pass through. The 

 term ' late blight ' came from the fact that 

 the Fhytophthora does not usually appear 

 before August. The early blight comes 

 sooner in the season, and usually the fun- 

 gus follows after some injury, frequently 

 the work of flea beetles. The earlier plant- 

 ings of the same variety are the more 

 affected by this blight. 



Bordeaux is a satisfactory remedy for the 

 late blight and a promising one for the 

 early blight. 



The cause of the scab is considered and 

 the corrosive sublimate both highly recom- 

 mended with the precaution that it be not 

 used so strong as to injure the seed. 



VARIETY TESTING OF POTATOES. 



Bulletin 65 Ohio Station is devoted to 

 the comparison of varieties of potatoes and 

 experiments with fertilizers, by Profs. 

 Green and McFadden. They maintain 

 that variety trials are of much value only 

 when the sorts are tested under several sets 



of conditions. It is the summing up of sets 

 of trials that brings results of practical 

 importance. Thus the three varieties that 

 have averaged highest at the central and 

 both sub-stations in Ohio are American 

 "Wonder, Columbus and Irish Daisy. Varie- 

 ties that are the least influenced by varia- 

 tions of soil, climate, etc., they claim are 

 the most valuable. 



GOVERNMENT FARMERS' BULLETIN UPON POTA- 

 TOES. 



In addition to the above station bulletin 

 the United States Department of Agricul- 

 ture has issued a farmers' bulletin (No. 35) 

 upon Potato Culture, by Mr. Duggar with 

 the following sub-heads : Soil and rotation, 

 manuring, varieties, planting, change of 

 seed, side of seed pieces, distance in the 

 row, mulching, storing, with a lengthy sum- 

 mary. This is a remarkably comprehen- 

 sive, condensed and clear exposition of 

 potato culture. 



The impression at least is gained from 

 the above notes that the potato is fully re- 

 cognized by experimenters as a leading crop 

 in the country and likewise a subject that 

 is many sided and as yet far too little un- 

 derstood. Byron D. Halsted. 



SCIENTIFIC NOTES AND NEWS. 

 SIB JOSEPH PEESTWICH. 



At the meeting of the Geological Society 

 of London, on June 24th, the President, Dr. 

 Henry Hicks, said : It is with deep regret that 

 I have to announce to you the death of our 

 dear and much-beloved friend, Sir Joseph Prest- 

 wich. He was elected into the Society in the 

 year 1833, and we had come to look upon him 

 as the father of our Society. He served it as 

 Treasurer and President and was one of its 

 Wollaston Medallists, and we feel that by his 

 death our Society loses one of its truest friends. 

 He always gave us of his best, and delighted to 

 communicate his knowledge to his fellow 

 workers. He was in every respect a typical 

 representative of our Society and its objects, for 

 he passionately loved the science, fearlessly 



