29 



4. Land barley from Grabschen was treated on July 3, 1903, as under 3b, but the fresh smut had 

 been taken from a field of Hanna barley. The seed, harvested from the infected blossoms and sterilized, 

 was sown, giving in 



IfiO stalks, 66 per cent of smutted ones. 



5. A variety of barley from Grabschen was infected in the separate blossoms on especially favor- 

 ably developed heads with fresh barley smut from the same field. The smut was shaken up in the dilute 

 nutrient solution and put on with a brush. Sowing of the infected grain, carried out as before, resulted 

 in 1904 in 



180 stalks, which with one exception were all smutted. 

 (Figure 1, plate 1.) 

 The control of 500 stalks from non-infected heads of the same barley had 2 smutted specmens. 



6. A two-rowed, small barley, which had never had loose smut and whose blossoms always remained 

 closed, was infected June 30, 1903, with fresh smut spores from a field of Hanna barley just as the 

 stigma in the artificially opened blossoms had fully developed. The grains obtained from the infected 

 blossoms were sown in 1904 as described above. Of 



160 stalks, 77 per cent were smutted. 



TI. CYLINDER INFECTION. 



1. Blossoming barley from Munster was infected in the cylinder with fresh smut spores from the 

 same barley field in Grabschen. The sterilized seed was sown in April, 1904, directly in the open field. 



500 stalks were developed, of which 12 per cent were smutted. 

 A control of 500 stalks had only one smutted specimen. 



2. Blossoming barley heads from a field in GrSbschen were infected in the cylinder early in July, 

 1903, with fresh smut spores from the same field. The sterilized seed was sown on April 6th, directly 

 on open ground 



400 stalks were developed, of which 20 per cent were smutted. 

 A control of 400 stalks from non-infected heads of the same field had 1 per cent of smut. 



3. The hlossoming^ heads of Hanna barley were infected in the cylinder in the beginning of June, 

 1903, with fresh smut spores from a barley field in Grabschen. From the sterilized seeds were grown 

 in 1904 



200 stalks, of which 9 per cent were smutted. 

 A control of just as many plants had no smut. 



in. INFECTION OP THE YOUNG GERMINATING SEEDLINGS. 



1. A variety of barley from Miinster, one from Grabschen and Hanna barley were planted in soil in 

 germinating cases and the equally developed young germinating seedlings were sprinkled as given above 

 with smut spores from the same field, still capable of germination. Of each variety 



600 stalks were developed, of which 1 or 2 specimens of each were smutted. 



IV. INFECTION OF THE SEED. 



Besides the barley from Miinster, Grabschen and the Hanna barley, a fourth variety was mixed 

 with smut spores and sown partly on well-manured farm land, partly on unfertile sandy soil. In each of 

 the 16 experiments 



200 stalks developed, among which there occurred only occasional smutted specimens. 



Entirely similar results were obtained in a corresponding control in which sterilized seed had been 



used. 



V. INFECTION OP THE SUBSTRATUM. 



Four different varieties of barley were grown in germinating cases, partly on good compost, partly 

 on a mixture of compost and fresh horse manure. The compost as well as the mixture with horse manure 

 was infected abundantly with spores of the foose smut of barley. The seedlings germinating in this 

 substratum and developed further were transplanted later to open ground and of each 

 200 stalks were grown. They were all free from smut. 



C. EXPERIMENTAL INFECTION IN 1905. 

 I. BLOSSOM INFECTION. 



1. Blossoming land barley in Grabschen was infected in June, 1904, in the separate blossoms with 

 fresh dry, loose smut of barley, simultaneously on two different fields, by three women. The sterilized 

 seed was grown in 1905 in closed cases on sterilized sand, then planted out in two separate beds. 



