38 BULiLETIlSr 817, U. S. DEPT. OF AGRICULTURE. 



given eggs of A. swum were still negative, while the check animals a few weeks 

 later were found positive. No conclusions can therefore be drawn from the 

 experiment. 



Experiment No. 18. 



The pigs used in this experiment were estimated to be between three and 

 four months old when received, December 21, 1916, but it was nearly two months 

 later before the first feeding with AscaHs eggs was given. 



Precautions were taken to prevent outside infection after the experiment 

 started and to insure that the animals were free from Ascaris before the 

 experiment commenced. Of the 12 pigs used, 10 were found to be infested 

 with Ascaris when purchased, and all 12 were given a dose of 2.5 mils of oil 

 of chenopodium, with 1 ounce of castor oil. In our extensive experience with 

 chenopodium Ave find that one dose is usually successful in removing all 

 Ascaris present. In order to make doubly sure, however, three treatments 

 with chenopodium were given, with intervals of five days to a week between 

 doses, the last dose being given January 15, 1917. Four days later the feces 

 of all the pigs were reexamined for Ascaris and all found negative. The ani- 

 mals were then taken from the pen, given a thorough scrubbing with soap and 

 water, so as to reduce the chances of Ascoris eggs being carried over on the 

 skin, and placed in clean pens with board floors, where no pigs had been 

 before. Two of the animals died during the preliminary treatment; the re- 

 maining 10 were placed in three pens, as follows : Pen A, 2 check animals not 

 given Ascaris eggs ; pen B, 4 pigs given 1 feeding of Ascaris eggs ; pen C, 4 

 pigs given repeated feedings of Ascaris eggs. 



PEN B PIGS GIVEN ONE DOSE OF ASCARIS EGGS. 



February 10, 1917 : Pigs dosed with Ascaris suum eggs from cultures started 

 December 14 and 29, 1916. Eggs from these cultures were also fed to mice, which 

 subsequently developed verminous pneumonia. 



INIarch 4, 1917 : Killed first pig 22 days after feeding Ascaris eggs. Five 

 Ascaris in the small intestine. 4 of which measured 8.5 cm., 7 cm., 7 cm., and 

 6.5 cm. The fifth, apparently about the same size, was cut by the enterotome 

 when the intestines were opened, and hence could not be measured. 



March 7, 1917: Killed second pig 25 days after feeding Ascaris eggs. No 

 A scaris found. 



March 21, 1917: Killed third pig 39 days after feeding Ascaris eggs. No 

 Ascaris seen in small or large intestine or stomach. No larvse found in spleen, 

 lurjgs, or liver. 



April 14, 1917 : Killed fourth pig 63 days after feeding with Ascaris eggs. 

 No Ascaris found. 



PEN C PIGS GIVEN REPEATED DOSES OF ASCARIS EGGS. 



February 24, 1917 : Pigs given first dose of Ascaris eggs. 



^larch 3, 1917 : Second dose of Ascaris eggs. 



aiarch 20, 1917 : Third dose of Ascaris eggs. Culture started February 27, 

 1917. This culture was subsequently fed to mice, and the resulting infestation 

 proved the embryos were viable. 



April 12, 1917 : Fourth dose of Ascaris eggs. 



April 27, 1917: Killed first pig 62 days after the first dose of Ascaris eggs, 

 15 (lays after the fourth dose. Two Ascaris in small intestine, 17 cm. and 19 

 cm., both the same age, to judge from their similarity in size. Liver, spleen, 

 lungs, esophagus examined microscopically for larvfe; none found. 



