June, 1913.] The Mosaic Disease of the Tomato. 169 



problem from an etiological standpoint. Curly-Top of sugar 

 beets has been an exceedingly baffling disease. Not until (190S) 

 did investigators grasp the situation and the cause was not dis- 

 covered until (1910). In this year Shaw proved it to be due to an 

 active agent introduced by the bite of the beet leaf ho])per. In 

 (1912) Bunzel devised his apparatus for measuring the oxidase 

 content of plant juices quantitatively, and applied it in detemiin- 

 ing the oxidase content of curly-top of beets in 1913, showing that 

 the leaves of curly-top plants have an oxidase content two or 

 three times that of healthy leaves. During the past year the 

 writer has made a study of an apparently similar disease of the 

 Raspberry, known as Raspberry Yellows or Curl, which although 

 never previously reported, has occurred quite abundantly in Ohio 

 for the last seven years. In addition to these, Peach Yellows, 

 Little Peach, Peach Rosette and other plant diseases have often 

 been regarded as enzymic diseases, but the writer knows of no 

 detailed investigations of the enzymes supposedly concerned. 



BIBLIOGRAPHY. 



Allard, H. a., 1912. The Mosaic Disease of Tobacco. Science n. s. 



36:875-876. 

 Appel, O. und Schlumberger, O., 1911. Die Blattrollkrankheit und 



unsere Kartoffelernten. Arbeiten der Deutschen Landwirtschafts. 



Gesellschaft. No. 190. 

 Bayliss, W. M. and Starling, E. H., 1902. The Mechanism of Pancreatic 



Secretion. Journal of Physiology. 28:325-353. (Not seen). 



, 1911. The Nature of Enzymic Action. 2nd. Ed. London. 



Behrens, J., 1896. Die Beziehungen der Mikroorganismen zum Tabakbau 



und zur Tabakfabrikation. Centralbl. f. Bakt.^ 2:515. 

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28: .) (1900. Rev. Zeitschrf. f. Pflanzenkh. 10:192-93.) 



Beyerinck, M. W., 1898. Over een contagium vivium fluidum als oorzaak 



van de Vleckziek te der tabaksbladen. Verslag Koninkl. Akad. van 



Wetensch. te Amsterdam, Wis. eu Natuurk. Afd. van Zaterdag. 6:229- 



235. (Same as German article cited below). 

 , 1898. Ueber ein Contagium vivium fluidum als Ursache der 



Fleckenkrankheit der Tabaksblatter. Verh. der Koninkl. Akad. van 



Wetensch. te Amsterdam. Tweede Sectie 6:5-22. PI. 1-2. 



(1899. Rev. Centralbl. f. Bakt. 25:27-33.). 

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 311. 

 , 1899. De'lexistence d'un principe contagieux vivant fiuide agent 



de la Nielle des feuilles de tabac. Archiv. Neerland. des Sc. Extractes 

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