156 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Sarcoptic mange of HORSES. — After four treatments with 10 per 

 cent solution of sodium hyposulphite the infected skin in cases of 

 horse mange showed decided improvement, and after seven treatments 

 the skin was apparently normal. The interval between treatments 

 was six days. In some cases a 10 per cent solution of acetic acid was 

 applied immediately following the application of the hyposulphite 

 solution. This method of treatment was not permanently success- 

 ful, as symptoms of mange again appeared tw^o months after the last 

 treatment. Repeated applications of a 25 per cent solution of sodium 

 hyposulphite followed by a 10 per cent solution of acetic acid proved 

 efficacious in curing mild cases of horse mange, but failed in ad- 

 vanced cases. 



External parasites of hogs. — Pine oil and 2 per cent emulsion of 

 pine tar proved less efficacious than crude petroleum as remedies for 

 lice and mange of hogs. 



Sheep scab. — In experiments on the protective action of various 

 dips against reinfection with sheep scab, lime-sulphur dip and nicotin 

 dip afforded protection for a period of 33 days after dipping. 

 Nicotin dip with 2 per cent flowers of sulphur added afforded pro- 

 tection for 69 days. 



miscellaneous investigations on animal' parasites. 



Investigations in regard to the anthelmintic value of carbon tet- 

 raehlorid have been carried on by tests against various worms in 

 chickens, dogs, swine, sheep, and cattle, and toxicity tests of this 

 drug have been made on these animals and on turkeys and rabbits. 

 The results confirm the conclusions drawn from previous experi- 

 ments on dogs, horses, and monkeys to the effect that carbon tetra- 

 chlorid is especially effective in removing bloodsucking nematodes 

 and is also effective in removing ascarids and some other nematodes. 



The drug has a large margin of safety between the effective thera- 

 peutic dose for removing certain worms and the lethal dose, in the 

 case of chickens and dogs. It is well tolerated by turkeys, rabbits, 

 swine, and monkeys, and apparently by horses. Ruminants appear 

 to be less tolerant of this drug than birds, rabbits, carnivores, swine, 

 and primates, but doses which remove all the stomach worms present 

 are tolerated without evidence of real injury and the efficacy of the 

 drug in removing stomach worms, other trichostrongyles, hook- 

 worms, and nodular worms from ruminants warrants further study 

 along this line to ascertain a safe and effective dosage. 



Following the work in this division in which the value of this 

 drug in removing hookworms from dogs was first ascertained, car- 

 bon tetrachlorid was brought to the attention of the medical profes- 

 sion as a drug worth testing in human medicine for removing hook- 

 worms. Reports up to the present time of tests along this line by 

 physicians in the service of the International Health Board of the 

 Rockefeller Foundation have been veiy favorable. Tlie drug has 

 been administered to more than 50,000 human hookworm patients 

 and has so far proved safer, more effective, less unpleasant in its 

 effects on the patient, and cheaper than the other drugs used for the 

 removal of hookworms. Carbon tetrachlorid is now established in 

 veterinary medicine as the best drug for the removal of hookworms 



