DISEASES OF PLANTS. 309 



not injurious to the plants; that corrosive sublimate and amnioniacal 

 copper carbonate act injuriously, injuring the germination; and that 

 hot water favors and hastens develoi)nient. 



Experiments v^ith the hot-^vater method for the prevention of 

 smut in spring grains, J. L. Jensen ( Tidsskr. Lundolion^ IS {isiH)^ pp. 

 o8o-o9s). — The exi)eri]nents were undertaken at the request of the 

 Koyal Agricultural Society of Denmark, and were conducted under 

 ordinary farm conditions. Plats were grown on 11 farms in different 

 parts of Denmark, the size of the plats ranging from 85 to 170 sq. ft. 

 Smutty barley and oats were distributed to the different farmers, the 

 seed furnished having received the following treatment: One lot each 

 of barley and oats untreated; one lot of barley soaked in cold water 

 for 4 hours, allowed to stand for G hours, and then dipped about 30 times 

 during 5 nunutes in water of 123° F. (50.0° C); one lot of oats dipped 

 during 5 minutes about 30 times in water of 129° F. (53.9° C.) (method 

 A); one lot of oats treated*as the preceding lot after 5 minutes' soak- 

 ing in cold water and subsequent standing for some hours (method B). 

 Five plats were thus sown to barley or oats at each farm taking part 

 in the experiments. 



Influence 0)1 ihe appearance of the .smut. — The treated barley seed gave 

 in all 3 smutty heads, against 00 heads in case of the untreated seed. 

 In the oats 2,70() smutty heads were found in all in the untreated seed, 

 471 in that treated by method A, and 2 in that treated by method B. 

 The treatment given in method A reduced the smut about four fifths. 

 In earlier experiments conducted in a similar manner this treatment 

 produced practically smut-free oats. In ISOl the following results were 

 obtained on 3 different farms, 4 plats having been grown of each kind 

 of seed at each place: 



NiDtihcr of sinuUji heruh of oats from Ireated (uid iiiitrcated seed. 



Lo..ality. Untreated. ^^^^ 



Nasgaard . 

 Lyiigby... 

 Dalum... .« 



The explanation of the difference in results obtained during 1893 and 

 l)revious years is that the smut appearing m all earlier experiments 

 was the open-oat smut, while that occurring in the experiments of 1893 

 was hidden smut.' 



The author was in 1893 able to prove that the hidden form of oat 

 sm ut IS a distinct species. Two varieties of oats were used for the exper- 

 iment, Danish White oats and Jutland Gray oats. Sixty grams were 

 treated according to the hot- water method, i. e., softened for 4 hours, 

 left standing moist for 8 hours, and then submerged in water of 131° F. 



'Kaus. Sta. Bui No. 15; abs. lu E. S. R., vol. ir, p. 638. 



