664 



Journal of Agricultural Research 



Vol. VI, No. 17 



EFFECT OF HEAT UPON THE VIRUS OF THE MOSAIC DISEASE 



Several investigators have noted the effect of heat upon the virus of 

 the mosaic disease. Mayer (17, p. 451) found that continued heating at 

 6o° C. did not perceptibly change the infectivity of the virus, but that 

 temperatures of 65 to 75 weakened it. Its infectious properties were 

 completely destroyed when the virus was heated for several hours at 8o°. 



Table XI. — Effect of heat upon the infectivity of undiluted solutions of mosaic virus 

 heated -without previous filtering, in IQ15, 10 plants having been used in each test 



Virus 

 used. 



Enzymic reaction 

 before treatment. 



Date and nature of 

 treatment. 



Enzymic reaction after 

 treatment. 



Date in- 

 oculated. 



Results. 



X 11 ... 



Do. 

 Do. 

 Do. 

 Do. 



Do. 



Do. 



Do. 



Do. 



Do.. 

 Control 

 X 85 



Do. 



Do. 



Do. 



Do. 



Do.. 

 Control 



Intense peroxidas 



.do. 

 .do. 

 .do. 

 .do. 

 .do. 



.do. 



.do. 



.do. 

 .do. 



do 



Strong peroxidase . 

 Intense peroxidase 



.do. 



.do. 



.do. 



.do. 



.do. 



do 



Strong peroxidase 



Heated 15 minutes at 

 82° C. in test tube sus- 

 pended in beaker of 

 water, Nov. 23. 



Boiled 1 minute in test 

 tube, Nov. 23. 



Boiled 5 minutes in test 

 tube, Nov. 23. 



Boiled 10 minutes in test 

 tube, Nov. 23. 



Unheated 



Heated 10 minutes at 

 85 ° C. in test tube sus- 

 pended in beaker of 

 water, Dec. 2. 



Heated is minutes at 

 85° C, Nov. 23; again 

 heated 7 minutes at 

 88° C, Dec. 3. 



Heated 10 minutes at 

 90° C. in test tube sus- 

 pended in beaker of 

 water, Dec. 2. 



Heated 10 minutes at 

 95 " C. in test tube sus- 

 pended in beaker of 

 water, Dec. 2. 



Heated 1 to 2 minutes at 

 ioo° C. in test tube 

 suspended in beaker 

 of water, Dec. 2. 



Unheated 



Tap water and healthy 

 juice, untreated. 



Heated 5 minutes at 85 ° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Heated s minutes at 87° 

 C. in test tuhe sus- 

 pended in beaker of 

 water. May 8. 



Heated 5 minutes at S8 ° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Heated 5 minutes at 90° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Heated 5 minutes at 91° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Heated 5 minutes at 93° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Heated 5 minutes at 95° 

 C. in test tube sus- 

 pended in beaker of 

 water, May 8. 



Unheated 



Tap water and healthy 

 juice, untreated. 



Good peroxidase, Nov. 

 24. 



do 



Weak peroxidase, 



Nov. 24. 

 do 



Intense peroxidase, 



Nov. 24. 

 Fair peroxidase, Dec. 



No peroxidase, Dec. 4 



Weak peroxidase, Dec. 



Very weak peroxidase, 

 Dec. 3. 



Fair peroxidase, Dec. 

 3- 



Intense peroxidase, 



Dec. 3. 

 Strong peroxidase, 



Dec. 4. 

 Good peroxidase, May 



.do. 



.do. 



Fair peroxidase, May 



.do. 



.do. 



Very faint peroxidase, 

 May 8. 



Intense peroxidase, 



May 8. 

 Strong peroxidase. 



May 10. 



Nov. 24 



..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 Dec. 3 



Dec. 4 



Dec. 3 



..do 



..do. 



Dec. 4 



..do 



May 10 



..do 



.do. 



.do. 



.do. 



.do.... 



.do. 

 .do. 



All healthy. 

 Do. 

 Do. 



8 mosaic. 



9 mosaic. 



All healthy. 

 Do. 



Do. 



8 mosaic. 

 All healthy. 



9 mosaic. 



All healthy. 



Do. 



Do. 



7 mosaic. 

 All healthy. 



