158 The Ohio Naturalist. [Vol. XIII, No. 8, 



under the most favorable growing conditions, with the virus 

 from tobacco plants. The inoculations had no effect. The virus 

 from the tomato had just as little effect upon the tobacco plant. 

 The tomato plants withstood the injections very nicely and did 

 not show the least signs of distortion." Clinton (1908) on the 

 other hand states that he succeeded in producing mosaic disease 

 on the tomato by inoculation with juice from a diseased tobacco 

 plant, and from this tomato plant he transferred the disease back 

 again to tobacco. 



[s Mosaic Disease Inheritable? — Investigators are almost unani- 

 mous in the opinion that "calico" of tobacco is not inheritable. 

 Woods (1902, p. 7 ) says, ''There is no conclusive evidence that 

 the plants from seed of diseased plants are more subject to the 

 disease than are those from the seed of healthy plants. " Iwan- 

 owski (1903) conducted inoculation experiments with crushed 

 diseased seed. He produced the disease in this manner just as 

 readily as where he used diseased leaves. He states (p. 15), 

 "From such facts one would conclude that the disease must be 

 inheritable, but experiments do not show this to be so. " In regard 

 to this characteristic of mosaic disease Sturgis (1899, pp. 247-8), 

 says that seed from diseased plants do not give rise to "calicoed" 

 plants. "It would seem apparent, therefore, that "calico" 

 is not communicable through the seed. I secured from the 

 seed bed — twenty seedlings showing "calico" and from the same 

 bed, twenty apparently healthy seedlings. These were^set in 

 two parallel rows in the garden — with one exception, all of these 

 forty plants were badly calicoed within six weeks. The exception 

 was one of the originally healthy plants — most of the plants 

 flowered and ripened an abundance of seed. This seed was sown 

 in flats in the greenhouse. Of the hundreds of seedHngs — thus 

 raised not a single one showed a sign of "calico" in the flats. 

 Thirty seedlings were transplanted and set in a row in the Station 

 garden — . All of the plants — showed great vigor and remained 

 perfectly healthy. Meantime, from the same lot of seedlings, 

 a dozen were sent to Mr. Ackley, who set them in a warm corner 

 near the barn — . These also failed to show any signs of "calico." 

 " Tomato mosaic is an inheritable disease in contrast with tobacco 

 mosaic." these are the conclusions of Westerdijk (1910, p. 20). 

 She kept the seed from apparently healthy looking fniit on a 

 diseased plant, separate from that of mottled fruits. She sprouted 

 the seed and the seedlings were transferred to the greenhouse, 

 test ]jlot and garden. Proper checks were used in all cases. 

 All plants grew equally well at first, but in two or three months 

 a noticeable difference was seen. In the field she raised 50 plants, 

 grown from diseased seed; the parent plants having been arti- 

 ficially inoculated. Also 40 were grown from diseased seed from 

 greenhouse plants. Of the latter, 20 originated from mottled 



