240. VINES 
to bear, it indicates that they are in need of 
nourishment. In this case, either apply a mulch, 
an inch or so thick, of good, rotted manure and 
soil in equal parts, or resort to liquid feeding. 
It is very difficult to clear a house of insects 
after they have obtained a foothold, especially 
the white fly, which is the most serious tomato 
pest in-doors. The only method is fumigation, 
the best material being hydrocyanic-acid gas. 
But this is very dangerous to animal life of any 
kind and should be handled only by responsible 
persons and with great care. I use four ounces 
of water, two of sulphuric acid, and one of po- 
tassium cyanide for every 2,000 cubic feet of 
space in the house. 
When about to fumigate, be sure all the venti- 
lators are down and all doors but one locked on 
the inside. Place an earthenware vessel contain- 
ing the water on the floor of the house, add the 
acid, then throw the cyanide, wrapped in tissue 
paper, into the vessel. Keep your face away 
from the dish while you do this, then quickly 
leave the house, locking the door to prevent any 
one from gaining access, and taking the key with 
you. Do not let anybody or anything enter the 
house until the next morning, when the venti- 
lators should be opened, from the outside, if 
