28 



Farmers' Bulletin 1057. 



raise :'t, throw it back to the entrance end, and haul through again, 

 repeaang as many times as necessary but always hauling through in 

 the same direction. 



The standard-strength bath prepared as above contains practically 

 0.19 per cent arsenious oxid when fresh. After use oxidation may 

 set in and weaken it, but it will not need to be strengthened so 

 long as it tests not less than 0,175 per cent arsenious oxid. 



To make up small quantities for spraying, to each 5 gallons of 

 water measured out add first 2 fluid ounces (4 tablespoonfuls) of 

 tar stock, and then 5^ fluid ounces of S-B stock or 2^ pints of 

 boiled arsenic stock. 



The standard strength of bath should be adhered to so far as 

 possible because its effectiveness against ticks will effect eradica- 

 tion in the least time and with fewest dippings. But if time is 

 not pressing it is sometimes best to begin with a lower strength, say 

 0.14 or 0.15 per cent, and gradually work up to full strength as 

 the cattle become accustomed to the treatment. This is certainly 

 a wise method for the individual cattle owner who is outside the 

 area of cooperative work and who lacks aid and advice from ex- 

 perts*. Weather conditions also need to be considered. Hot or moist 

 weather is more trying to the cattle than cool or dr}'^ weather. The 

 longer the time needed for the cattle to dry off after dipping, which 

 of course primarily depends on the proportion of moisture in the 

 air, the more liable they are to shoNv blistering or other injury 

 through the continued absorption of arsenic by the skin. The com- 

 bination of heat and moisture is particularly bad and under such 

 conditions it may be desirable, unless other conditions prohibit, to 

 use the bath somewhat weaker than standard strength. The fol- 

 lowing table shows the quantities of arsenic and stock solutions con- 

 tained in 100 gallons of bath of different strengths, so that the 

 quantities necessary to charge a vat of any size at any strength can 

 be found by simple multiplication. 



Tablk 4. — Composition of dipping baths. 



