THE EEAKING OF SILKWOEMS. 17 



Ventilation. 



The domesticated worm should be surrounded continually by pure 

 air. The amount of carbonic-acid gas g-iven out by the worms and 

 their attendants is very considerable; besides this, a quantit}' of dele- 

 terious gas is generated by the litter of the beds, and the lights and 

 fires consume a great deal of oxygen. Myriads of spores and germs 

 of organic life float in the air of the rearing- room, and their influence 

 paralyzes the vital energy of the skin and of the organs of respiration, 

 on whose normal functions the robustness of the worm so much depends. 

 Hence, it is evident that the quantity of vitiated air which should be 

 expelled from the room requires the introduction of a large quantity 

 of fresh air. For this, a double system of ventilation is necessary, 

 which may be obtained by double openings in the windows, to allow 

 the heated bad air to pass out above and the cool fresh air to come in 

 below. To renew the air in every part of the room, and to avoid a 

 single and often violent current, there should be more than one win- 

 dow. An open fireplace is the best means of ventilation. When the 

 difference between the external and internal air is slight, or there is no 

 difference at all, artificial means must be used to create a current. 

 Light and frequent fires, or a burning lamp in the fireplace, or a 

 revolving fan, may be used to prevent stagnation of the air. 



Disinfection. 



Eight or ten daj's before introducing the worms into their quarters 

 all the shelves and implements should be washed in a solution of chlo- 

 ride of lime (11 pounds of chloride of lime to 88 quarts of water), or 

 in a solution of sulphate of copper (1 to 100 by weight). 



When everything is in order — tools, perforated paper, material for 

 the worms to spin their cocoons on, etc., each in its own room — close 

 the doors and windows as tightly as possible and fumigate the rooms 

 with sulphur (11 pounds of sulphur to every 100 cubic yards of space). 

 To fumigate properly, powder the sulphur and place it in an earthen 

 or metallic vessel over a slow fire. The sulphur will gradually melt 

 and take fire. Place it immediately in the rearing room and leave it 

 there, with the doors and windows completely shut, for twenty-four 

 hours. 



Nets should not be exposed to sulphur fumes, for this would soon 

 rot them, but should be washed in a solution of sulphate of copper, and 

 immediately afterwards in plain water. 



Twent3^-four hours after the fumigation the floors should be washed 

 with a solution of chloride of lime or sulphate of copper, and the walls 

 should be whitewashed with lime. 



When dead worms are seen on the shelves, change the beds and create 

 in the rearing room sulphurous gas by burning a pound of sulphur 

 during six hours, or make a strong wood smoke, which is a good disin- 

 fectant and will not harm the worms. 

 16615— No. 39—03 2 



