juiy 2 4 , i 9 i6 Properties of the Virus of Mosaic Disease 



661 



was again dried at room temperatures and macerated with 20 c. c. of dis- 

 tilled water. The results of inoculation experiments with this material 

 are shown in Table IX. 



Table IX. — Infectivity of green mosaic leaf material after digestion with ether, chloroform, 

 and water, October 20 and 21, igi 5, 10 plants having been used in each test 



Material used. 



Time required 



for extract to 



evaporate. 



Date 

 taken up Peroxidase reaction after di- 

 with wa- 1 gestion. 



ter. 



Results of inoc- 

 ulating plants 

 Oct. 25, 1915. 



Green residue after digestion 



with ether. 

 Ether solution from above. . . 

 Green residue after digestion 



with chloroform. 

 Chloroform solution from 



above. 

 Green residue after digestion 



with water. 

 Water solution from above. . . 

 Tap water (control) 



Oct. 21 to 23. 



Oct. 21 to 22. 

 Oct. 21 to 23. 



....do 



....do 



Xot evaporated . 



Oct. 23 



Oct. 22 

 Oct. 23 



.do., 

 .do.. 



Intense peroxidase, Oct. 23. 



Good peroxidase, Oct. 25 . . . 

 Intense peroxidase, Oct. 23. 



do 



Good peroxidase, Oct. 25. . . 

 Intense peroxidase, Oct. 23. 



10 mosaic. 



6 mosaic. 

 10 mosaic. 



9 mosaic. 



10 mosaic. 



Do. 

 All healthy. 



From Table IX it is evident that the infective principle of the virus 

 was not killed in the ether or chloroform solutions. From similar experi- 

 ments Clinton (8, p. 415) believed that ether and chloroform could ex- 

 tract the virus from the green leaves to some extent without injury to 

 its infectious properties. 



However, from the fact that green crushed material contains a large 

 amount of water, it is very probable that some of this water containing 

 the infective principle passes into the ether or chloroform solutions. Such 

 solutions would represent little more than mixtures of virus and ether, 

 etc. Although the infective principle and likewise peroxidase appeared 

 in the ether and chloroform solutions when green material was used, 

 these did not appear in ether or chloroform extracts made with dry 

 material. 



The fact that the infective principle, or even enzyms, appeared in 

 solutions obtained by adding ether, chloroform, toluene, etc., to green 

 material does not justify the conclusion that such substances are soluble 

 in these solvents. Kastle (13, p. 16), working with the oxidases of Lepiota 

 americana, found that if toluene is added to portions of the fresh fungus, 

 some of the oxidase passes into the toluene layer. He says : 



Whether the perfectly dry oxidase is soluble in toluene remains to be proved. It 

 may be, of course, that it is the water which is dissolved in the toluene which really 

 takes the oxidase into solution. 



Various experiments have shown that the infective principle of the 

 mosaic disease of tobacco is not readily destroyed by ether, chloroform, 

 toluene, or carbon tetrachlorid. Although ether or chloroform vapors 

 quickly kill the green leaf, the infective principle in a mosaic leaf killed 

 in this way remains uninjured after several hours' treatment. Likewise 



