30 



In bed 1, 600 stalks developed, of which 58 per cent were smutted. 



" " 2, 660 " " " " 44 



Equally large controls of the same barley had no smut. 



2. Blossoming barley from another field was Infected on June 28, 1904, with fresh barley smut, in 

 two different places as under 1. The smut spores were shaken in water and put into very dilute nutrient 

 solution. The harvested seed gave in the following year 



In bed 1, of 250 stalks, only 13 per cent smutted ones. 

 " 2, " 200 " " 16 " 



The control had no smut. 



3. The blossoms of a two-rowed cleistogamous barley which had never had smut were infected in 

 June, 1904, with fresh smut of a barley (land barley from Grabschen). The following year 



250 stalks developed, of which 30 per cent were smutted. 



II. CYLINDER INFECTION. 



1. In a barley field in Grabschen, shortly before blossoming, the still closed blossoms were infected 

 in two separate places on June 22, 1904, in the cylinder with fresh loose smut of barley. The sterilized 

 seed was sown in two different beds. 



In bed 1, 540 stalks were developed, of which 9.5 per cent were smutted. 

 " 2, 670 " " " " " 9.7 " 



2. The same barley was later infected in the cylinder, shortly after it had bloomed. 



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

 A control of the same barley had no smut in 2,000 stalks. 



III. INFECTION OF THE GERMINATING SEEDLINGS. 



Seed of different ages was used on fields in which no loose smut or very little had been observed. 

 Most of the smut spores used in 1904 were still capable of germination. The experiments were carried 

 out exactly as was described for the experiments of the germinating seedlings in wheat in 1905. There 

 were used 



Probsteiner barley from 1900-1901-1902-1903 and 1904, 

 and Chevalier barley from 1900-1901-1902-1903 and 1904. 

 In all ten experiments no smut appeared. 



IV. INFECTION OF THE SUBSTRATUM. 



The experiments were carried out with the varieties named under III, exactly as was described for 

 wheat in 1905, in the same place. Here, too, no smut appeared in all ten experiments. 



From the experiments with loose smut in wheat and barley, which thus correspond 

 exactly, the infection of the blossom has become a scientific fact. The smutted appearance due 

 to the loose smut in the grain fields of wheat and barley has brought forward a newly discovered 

 form of infection of which no one had thought before. The infection of the young germinating 

 seedlings which had previously been considered as the only active one, can count for little, 

 perhaps for nothing at all, in comparison with infection of the blossoms. The new fact is of itself 

 of high scientific value. Its characteristic nature is first shown by the fact that the infection in 

 its greatest action is entirely withdrawn from observation. The germs of infection tvhich pene- 

 trate to the young ovaries remain hidden in these and even until complete ripening do not 

 develop fructificatively, nor indeed even at the very point where the smut masses are otherwise 

 always and solely formed. Not one trace may be seen outwardly on the infected and harvested 

 seed of any smut infection which has already taken place. The anatomic condition proves that 

 smut spores are present in the seed and remain quiet during its dormant period. The infection 

 is temporarily interrupted by this dormant seed period and, after this is passed, is continued with 

 the further development of the plant. Only in the germination of the seed can the fungus develop 



