BUREAU OF ANIMAL INDUSTRY. 381 



as a sure cure for internal parasites, was tried, but this likewise 

 I)roved to be inefficacious not only against the fringed tapeworm, but 

 also against other parasites. A report of these treatment experiments 

 IS given in Bulletin 155. 



CATTLE MANGE. 



Under the supervision of Dr. Charles Pearson, of this bureau, an 

 experiment was conducted in northwestern Texas in the treatment 

 of cattle mange with nicotin dip from which the sulphur required 

 under the present regulations governing official dippings was omitted. 

 Twenty-eight cattle showing well-marked cases of mange were selected 

 from a herd of about 800. .and these were dipped in nicotin solution 

 without sulphur, the remainder being dipped in the usual nicotin 

 and sulphur dip. The first dipping Avas done on November 21, and 

 the second dipping on December 4. On inspection, January 5 and 

 February 2, none of the 28 experimental animals showed evidence of 

 the presence of active mange. Finally an inspection of the entire 

 herd, including the 28 that were dipped in the nicotin solution with- 

 out suli:)liur, was made on April 24, 141 days after the second dipping, 

 and the herd was found to be free from mange. 



The dipping solution from which the sulphur was omitted con- 

 tained about 0.08 per cent of nicotin. The results of this experiment 

 indicate that nicotin dips without sulphur are efficacious remedies for 

 cattle mange. Further trials of nicotin solution at 0.07 per cent 

 strength are now in progress under the supervision of various inspec- 

 tors on the field inspection force of the bureau. 



INVESTIGATION RELATIV^E TO TICK ERADICATION. 



Experiments are in progress to determine the length of time after 

 dipping that arsenical dips protect cattle against infestation with 

 ticks. It has been demonstrated that when cattle are dipped 

 repeatedly in arsenical solutions at intervals of two weeks arsenic is 

 stored up in the skin in small quantites. Apparently, however, this 

 has no influence in protecting against tick infestation if a week or 

 more elapses after the last dipping before the cattle are exposed to 

 infestation. On the other hand, it appears that a single dipping is 

 sufficient to protect cattle against infestation during a short period 

 after dipping. Whether this protection lasts only a few hours or one, 

 two, or more days remains to be determined. Further information on 

 this important point will be available when the experiments now 

 under way are finished. 



INVESTIGATIONS CONCERNING PARASITIC PROTOZOA. 



An investigation of the life history of the Sarcosjioridia. concern- 

 ing which practically nothing is known, has been undertaken and a 

 number of points of importance have already been determined. 



Gastrocystls r/ilrufhi, a sarcosporidian j^arnsitic in the wall of the 

 fourth stomach, has been found in slieep in this country. 



A number of cases have been observed in western sheep in which 

 Sarcocystis tenella formed nodules in the diaphragm and heart which 



