80 



priority, gave the name Clasterosporium carpophilum (Lév.) Aderh. 

 Beijerinck in 1906 resigned himself to this change of name, but took 

 up the subject again in 1914, declaring that he preferred to join in 

 with OuDEMANs' authority and to maintain the name C. Beijerinckii. 

 It will appear that Beijerinck always considered this organism as the 

 most potent cause of the occurrence of gummosis, and anyone who, as 

 the writer, has been permitted to follow Beijerinck's experiments, 

 will be convinced that he was right in this matter. 



In the treatise of 1883 Beijerinck stated the opinion that a pri- 

 mary infection by the said fungus is necessary for the occurrence of 

 the gumming disease in the Amygdalaceae. He supposed that Coryne- 

 um excretes a "ferment" which changes the cell-walls into gum, and that 

 sometimes produces the same change for the cell-walls of the fungus. 

 This enzyme, however , should react f urther with the protoplasm of living 

 cells in such a way that these cells, sometimes even after they had 

 divided, should produce this same enzyme and should change their 

 cell-walls into gum. In this manner the disease of the infected parts 

 could be transmitted into healthy parts without the latter being 

 reached themselves by the mycelium. 



In an extensive final paragraph Beijerinck discusses then the rea- 

 sons that lead him to the conclusion that the f ormation of gum arabic, 

 also, is caused by an infection with a related fungus. He had received 

 the material necessary for this conclusion while visiting the Kew 

 Botanical Gardens. 



We emphasize here that in this treatise there is no question of the 

 isolation of fungi, and thus also no question of infection experiments 

 with pure cultures. According to later Communications, Beijerinck 

 began with such isolations in 1886, and succeeded in obtaining a high- 

 ly virulent spore-forming culture of Coryneum Beijerinckii. We have 

 already mentioned above that he sent a pure culture to Aderhold, 

 who published in 1902 an interesting treatise i) on the relation between 

 the gum exudation (Gummifluss) and this organism, in which he 

 completely confirmed Beijerinck's conception that the said fungus 

 produces gummosis; Aderhold added, however, that further in- 

 vestigation was needed as to whether perhaps also other causes 

 produce gum exudation. 



It was presumably this treatise which reawakened Beijerinck's 

 interest in the subject of gummosis in the years following 1902, 

 coupled with the f act that a young biologist, A. Rant, a student of 

 Amsterdam University, expresséd the desire to study this subject under 

 his direction. In 1906 there appeared a joint publication, and in the 

 same year a dissertation on the subject was offered by Rant in Am- 

 sterdam 2). 



1) K. AT>'ERB.ohT>,XJher Clasterosporium carpophilum (Lév.) Aderh. und dessen Be- 

 ziehungen zum Gummifluss, Arbeiten der biologischen Abteilung des Gesundheits- 

 amtes 2, Heft 5, 515, 1902. 



2) A. Rant, De gummosis der Amygdalaceae, Dissertatie Amsterdam, 1906. 



