246 



EXPERIMENT STATION. 



[Jan. 



Set Numbers. 



Time of exposure, . 

 Length of exposure, 

 Temperature (degrees), . 

 Humidity (degrees), 

 White Spine, 

 Hothouse 



From the last three experiments it is evident that even an 

 electric light near the plants which are being fumigated has 

 an effect iii)on them. 



Comments and General Conclusions. 



BY C. W. HOOKER. 



1. Day fumigation in direct sunlight is unquestionably un- 

 safe, as the plants are badly injured or killed. 



2. Fumigation on a cloudy day is unsafe at best, the jtlants 

 being generally more or less injured. 



3. Fumigation on a bright moonlight night is also unsafe, 

 often causing much burning of the foliage. 



4. The best results are obtained by fumigating on clear 

 starlight nights, Avith little or uo moonlight, and on dry, cloudy 

 nights. 



5. A clear, dry evening without moonlight, with a tempera- 

 ture in the house of from 55 degrees to 65 degrees, or a cloudy 

 evening with the same temperature, offer the best conditions 

 for fumigation. This should be followed by a thorough venti- 

 lation for at least fifteen minutes, and the temjoerature should 

 be kept rather low for twenty-four hours thereafter, 



0. A general survey of the experiments seems to indicate 

 tluit a small amount of KCN with a longer exposure is pref- 

 erable, to a large amount for a shorter exposure. 



7. Individual results obtained here and there in the course 

 of these experiments which seem to contradict the others may, 

 in general, be accounted for by the condition of the plants. 



