DDT Formulations 87 



had, but today there are a wide variety of synthetic substances 

 that are much more effective than soap. These materials 

 come on the market under a variety of trade names, a few of 

 which are Emulphor, Chovis, Mulag, Tween, and Tegin. 



The quantity of emulsifying agent needed is not very 

 great. For example, a good 30% DDT concentrate for 

 emulsion purposes can be made by dissolving 30 parts by 

 weight of DDT and 4 parts of an emulsifying agent in 66 

 parts of xylene. 



Since these concentrates are made with organic solvents 

 such as xylene, they are inflammable, just like the ordinary 

 5 % DDT-kerosene solution. Furthermore, the concentrate 

 must never be used as such on animals or plants. Not only 

 is the DDT concentration too great for direa use, but the 

 solvent itself might cause damage. 



To make a 5 % DDT emulsion from a 30 % concen- 

 trate, you simply stir one part of the concentrate into 5 parts 

 of water. Because of the large amount of water in propor- 

 tion to solvent, the emulsion is nonflammable. Thus, it 

 makes a nice product to apply to the walls of barns and other 

 buildings as a residual spray for the control of flies. How- 

 ever, it should not be used in homes because the water would 

 streak and stain your pretty wall paper. 



Also, because of the low concentration of solvent in the 

 finished emulsion, emulsion sprays can be used on animals 

 as well as on plants. But for use on plants, you will want to 

 dilute the concentrate to make a spray with only about % or 

 1 % DDT. So follow the direaions on the bottle before 

 going after the bugs. 



Powders That- Wet 



Well, if you can dissolve DDT in a solvent and then 



