636 Journal of Agricultural Research voi. xiii. no. 12 



possessed no infectious properties whatever, while the soil preparation 

 and the original bottled \'irus were still infectious. 



In an additional test 50 c. c. of virus were mixed with 72 gm. of 

 kaolin, U. S. P. Thirty-two days later this material still possessed in- 

 fectious properties. When tested again, 61 days later, it no longer 

 possessed them. 



In a test carried out in March, 191 7, 200 gms. of finely screened green- 

 house soil were mixed to a stiff paste with 50 c. c. of freshly extracted 

 sap obtained from mosaic plants. One hundred gms. of talc, U. S. P., 

 were mixed with 75 c. c. of fresh virus from the same source, and 100 gm. 

 of finely ground, pure quartz sand were mixed with 25 c. c. of virus. 

 A portion of the original virus was set aside in a bottle. The sand, 

 soil, and talc pastes were kept in glass jars and covered with a sheet of 

 heavy paper tied over the mouth. In November, 231 days later, inocu- 

 lation tests were made with this virus. The talc and soil preparations 

 appeared to have completely lost their infectious properties, but the 

 sand preparation and the original, bottled virus were highly infectious. 



Koning's ^ experiments led him to believe that the soil in some manner 

 destroyed the infective principle of the mosaic disease. Heintzel ^ was 

 also of the opinion that the soil weakened the infectious principle of the 



disease. 



SUMMARY 



Nitric and hydrochloric acids had little effect upon the infectivity of 

 the virus, except in concentrations approaching i gm. in 50 to 100 c. c. 

 of virus solution. Phosphoric, citric, and acetic acids were vidthout 

 effect, except in concentrations approaching i gm. in 20 to 50 c. c. of 

 virus solution. 



The virus was more sensitive to the effect of sodium hydroxid than to 

 sodium carbonate. 



Manganese sulphate, sodium chlorid, aluminium sulphate, lithium 

 nitrate, sodium nitrate, lead nitrate, and silver nitrate had little effect 

 upon the infectivity of the \'irus. 



Mercuric chlorid affected the virus but little. 



Potassium permanganate and zinc chlorid affected the infectivity of 

 the virus only in concentrations stronger than i gm. in 100 c. c. of virus 

 solution. ' 



Under certain conditions the copper sulphate has shown itself rather 

 toxic to the infective principle. 



Carbolic acid, Creolin, cresol, and Phenoco have affected the infective 

 principle but little under the conditions of the experiments, and there 

 appears to be no appreciable difference in their effects. Phenoco, 

 although having a phenol coefficient of 1 5 when tested upon the typhoid 



* KoNiNG, C. J. OP. tiT. 2 Heintzel, G. E. op. cit. 



