New York Agricultural Experiment Station. 215 



tubers. Accordingly, the following experiment was made: Eighty 

 cubic centimeters of 37 per ct. formaldehyde solution were mixed 

 with 1600 cubic centimeters of distilled water thereby making a l-to-21 

 solution. Ten successive lots of unsprouted tubers were each soaked 

 two hours in this solution. Each lot contained as many tubers as the 

 solution would cover, i. e., the solution was used to its full capacity each 

 time. The total number of tubers treated was 165 and their total 

 weight 41 f lbs. The tubers were thoroughly washed before treat- 

 ment. With different lots the temperature of the solution varied 

 from 17 to 22 degrees C. After treatment the tubers were dried 

 and then stored in a dimly-lighted room. The tubers of all ten lots 

 showed slight lenticel spotting, Lot No. 10 being quite as much 

 affected as Lot No. 1. Lots No. 1 and 10 were kept under obser- 

 vation for 16 days. Both lots sprouted vigorously and, apparently, 

 in a normal manner. So far as could be determined from the effect 

 on the tubers the strength of the formaldehyde solution had not 

 been weakened. This conclusion is confirmed by the results of 

 chemical analyses made by the Chemical Department of the Station. 

 The solution which had been used ten times was found to contain 

 2.01 per ct. formaldehyde while a portion of the solution which had 

 not been used contained 2.02 per ct. formaldehyde. 



HOW SHOULD THE FORMALDEHYDE GAS 

 TREATMENT BE MADE? 



In the light of this investigation how should the formaldehyde 

 gas treatment be applied? First of all, it may be said that the gas 

 treatment should be used only in cases in which it is impracticable 

 to use either of the liquid treatments. The safety and efficiency 

 (for scab) of the liquid treatments have been thoroughly established. 

 With our present knowledge, the gas treatment as recommended by 

 Morse may be applied with entire safety provided the fumigation 

 chamber contains at least ten pounds of potatoes per cubic foot of space; 

 but it is uncertain what effect this will have on the efficiency of the 

 treatment. That it is possible to secure efficiency without injury 

 to the tubers is indicated by Morse's experiment at Houlton, Maine, 

 although as Morse himself states, 44 the fact that so little scab (6.5 

 per ct.) developed from the untreated seed detracts somewhat from 



* Me. Sta. Bui. 149 : 313. 



