NISHIMURA: A CARRIER OF THE MOSAIC DISEASE 231 
Tabacum were inoculated with juice of the mosaic-diseased tobacco 
and forty-eight of these plants showed the disease. 
2. The same test was made with the juice of mosaic-diseased 
Solanum aculeatissimum on twenty-nine healthy plants of P. 
Alkekengi, and none showed any symptoms of the disease. Of 
forty healthy plants of S. aculeatissimum inoculated with juice of 
mosaic-diseased S. aculeatissimum thirty-three plants showed the 
disease. 
3. Of thirty-one healthy plants of N. Tabacum inoculated with 
juice from leaves of P. Alkekengi which showed no symptoms of 
mosaic but had been inoculated from diseased tobacco or S. acu- 
leatissimum, twenty-two plants showed typical mosaic disease. 
Of twelve young healthy plants of N. Tabacum inoculated with 
juice from leaves of P. Alkekengi which had not been inoculated 
none showed the disease. 
4. Of thirty-two healthy plants of S. aculeatissimum inocu- 
lated with juice from leaves of P. Alkekengi which showed no 
symptoms of mosaic but had been inoculated from diseased 
tobacco or S. aculeatissimum, twenty-one plants showed’ mosaic 
also. Of twelve young healthy plants of S. aculeatissimum 
inoculated with juice from leaves of P. Alkekengi which had not 
been inoculated, none showed the disease. 
5. Experiments have shown that the mosaic diseases of S. 
aculeatissimum and N. Tabacum are similar with respect to the 
symptoms and incubation periods. 
6. The juice from diseased N. Tabacum when passed through 
P. Alkekengi to N. Tabacum has produced the disease,in 80 per 
cent. of the inoculations on healthy plants of S. aculeatissimum or 
N. Tabacum. It is evident that there is no marked weakening 
of the virus by the carrier P. Alkekengt. 
The author is especially indebted to Professor Harper of 
Columbia University for his kindly interest and valued super- 
vision throughout these experiments. 
DEPARTMENT, OF BOTANY, 
COLUMBIA UNIVERSITY 
