I50 The Ohio Naturalist. [Vol. XllI, No. 8, 



attention to this tobacco trouble, stating that it had occurred in 

 the East Indies in 1888. The next investigator ot this problem 

 whose work attracted attention, was Iwanowski (1892, 1899, 

 1903), who most emphatically pronounced mosaic disease to be 

 bacterial in nature. PrilHeux and Delacroix (1894), describe 

 the disease, believing that it is similar in nature to a spot disease 

 occurring on Cyclamen. Marchal (1897), mentions mosaic dis- 

 ease and its treatment. Koning (1897), describes specific organ- 

 isms which are supposed to be associated with this disease. Bey- 

 erinck (1898), and vSturgis (1N99), both published papers. The 

 former author propounded the "contagium vivium fluidum" 

 theory, while Sturgis regarded it as a physiological trouble. 

 The following year (1900), Sturgis published the results of ex- 

 periments in shading and liming tobacco plants. Woods (1899) 

 presented his paper on the destruction of chlorophyll by oxidizing 

 enzymes, with special reference to mosaic disease. According to 

 Hunger (1905, p. 262), Dr. van Breda de Haan (1899), isolated 

 bacteria from the tis.sues of diseased plants, said to be affected 

 with mosaic. In (1900) Heintzel published a paper on tobacco 

 mosaic and Behrens mentioned a disease of the tobacco which 

 resembled mosaic in its symptoms and characteristics. Gontiere 

 (1900), in a short review gives recommendations for treating 

 seed and seed-beds. Woods (1902) revolutionized the interpre- 

 tations of this malady, by propounding his enzyme theory and 

 Hunger (1902, 1904), believed that he had eliminated bacteria 

 as the causal organism. But nevertheless in the following year, 

 Hunger (1903) (a) severely criticised Woods' enzymic theory. 

 Suzuki (1903) studied a peculiar variegation of the leaves of the 

 mulberry, obtaining results similar to those of Woods' on tobacco. 

 Hunger (1903) (b) published other work explaining some of the 

 ways in which this disease is spread. In the same year Boyugues 

 (1903). cites definite data, dealing with the incubation of mosaic 

 disease; he also seems to have made an anatomical study of the 

 trouble. That laborers are responsible for the sj^rcading of this 

 disease in part, is shown by Hunger (1903). Selby (1904) con- 

 firmed some of Hunger's infection experiments, showing that 

 the disease could be disseminated by alternately touching dis- 

 eased and healthy plants. In (1905) Hunger juiblished a detailed 

 treatise on mosaic disease, treating of its history, theories and 

 experimental data. Delacroix (1905) found that a bacillus is 

 associated with mosaic disease, and gave its exact measurements. 

 Clinton (1908) mentions tomato chlorosis and its characteristics; 

 he speaks of a similar malady on lima bean. Later (1910) he 

 mentions as similar troubles, chlorosis of the squash, muskmelon 

 and tobacco. Tomato mosaic is treated and compared with the 

 same disease of tobacco by Westerdijk (1910). Loedwijks (1910) 

 shows how colored light and light intensities effect the behavior of 



