AGRIODLTDRAL EXrERIME>'T STATION. 103 



hour and a half in a sohition of corrosive sublimate or Bordeaux 

 mixture, to kill any germs present. 



EXPERIMENT. 



To test the efficacy of treating the seed with corrosive sublimate 

 we took some potatoes that were slightly scabby and divided in two 

 lots, one of which was treated two hours in a solution of 2 ounces 

 to 16 gallons of water, and the other not. A portion of the un- 

 treated seed was planted, adjoining on each side of the treated. 

 All was fertilized and cultivated the same. The soil had not grown 

 potatoes for four years 



The untreated seed came up before the treated and the tops ap- 

 peared more vigorous during the whole season and obtained a 

 fourth greater growth, and the weight of tubers was much more. 

 All the potatoes were about equally scabby. 



CONCLUSIONS. 



1. That the germs of potato scab will retain their vitality in 

 the soil for at least four years, as shown. 



That if the germs are in the soil the treatment of the tubers with 

 corrosive sublimate will not prevent the disease, and is apparently 

 of no advantage. 



That corrosive sublimate has a poisonous effect upon potato 

 plants, depressing their vigor and lessening the yield, when the 

 tubers are treated for two hours. (Our observations agree with 

 those of Professor Taft, who says (Mich. Expt. Sta. Bull, No. 108) 

 that treatment for longer than one and a half hours lessens the 

 amount of scab but reduces the yield. 



The only advantage then in the use of corrosive sublimate solu- 

 tion is when suspicious seed is to be planted upon nncontaminated 

 soil. 



FORMULA . 



Dissolve two ounces of corrosive sublimate in two gallons of hot 

 water and then add fourteen gallons more before using. Remem- 

 ber that corrosive sublimate loill corrode any metal vessel and a 

 ivooden receptacle should be used. 



Soak the seed in this solution for one and a half hours, dry, and 

 it is ready to plant. 



