410 ' REPORT OF THE COMMISSIONER OP AGRICULTURE. 



medicines. Third, I considered it as desirable to subject the vitality, 

 or rather efLectiveness of the Schizomycetes, or of the infectious princi- 

 ple, to a practical test after they had been preserved for a long time 

 (nearly a year) in a suitable vehicle outside of the animal organism. 

 In order to decide these i^oints, I procured three perfectly healthy and 

 vigorous pigs, free from any Tvounds or sores, each about four or five 

 months old, and weighing about ninetj^ pounds. (The three together 

 weighed 205 pounds.) In the midst of a large empty lot, on high and 

 dry ground, and inclosed by a good substantial board fence, which 

 permitted no animal larger than a chicken to crawl through, I built 

 them a pen of new lumber especially designed for my purpose. The 

 pen measured 12 by 8 feet, had a good board floor and a board roof, 

 and was divided by partitions, 4 feet high, into three separate apart- 

 ments, each 8 by 4 feet. The troughs, one for each apartment, were so 

 made as to facilitate cleaning and removing of the same if desired. I 

 received those pigs on January 0, kept them a few days for observation 

 as to their health, and commenced my experiments on January 11. It 

 was at fii^st my intention to procure for two of these pigs some water 

 from an infected creek or streamlet, but winter weather, frost, bad 

 roads, and a distance of seven miles or over between Oquawka and the 

 nearest streamlet known to be infected, caused me to abandon that pro- 

 ject, and induced me to substitute well-water infected on purpose with 

 infectious material. I procured the latter — pulmonal exndation, which, 

 undoubtedly, is neither as infectious, nor does it contain such an im- 

 mense number of Schizomycetes as the excrements and other excretions 

 of a diseased pig — from Mr. Graham's herd. The water was drawn 

 fresh (three times a day) from a good well, poured into the troughs, and 

 then contaminated or infected for each pig, Kos. 1 and 2, with a few 

 drops of the pulmonal exudation. Pig No. 1, wliich occupied the west 

 end of the pen, and pig Ko. 2, which was kept in the middle apartment, 

 received such infected water for drinking tluring four successive days, 

 or fi'om the evening of January 11, till noon January 15. Pig No. 1 

 received no medicine whatever, and pig No. 2 received each time, 

 together with the pulmonal exudation, six or seven drops of the con- 

 centrated carbolic acid (95 per cent, of Malliuckrodt'S cryst. carbolic acid, 

 and 5 per cent, of water) in the water for drinking. Pig No. 3, occupy- 

 ing the eastern part of the pen, was subjected to another experiment, 

 and received clean water, clean food, and no medicines of any kind. 

 Last winter (in January, 1879), while investigating swine plague in Lee 

 County, I had occasion to filtrate infectious pulmonal exudation, some- 

 what dilitted with water, for the purpose of freeing the same from the 

 Schizomycetes or disease-producing germs. I made repeated efforts, 

 and used filtering paper, but did not succeed. The filtrate, however, 

 which was perfectly clear, was preserved in a vial with a tight-fitting 

 glass stopi}er. Eepeated microscopic examinations (April 13, July 26, 

 November 15, and January 11) showed that the Schizomycetes had not 

 disappeared, and had undergone but very slight changes {cf. drawing. 

 Fig. XV). It was therefore to be supposed that the filtrate, which was 

 yet clear and transparent, and without any smell whatever, might stUl 

 possess its infectious properties. Consequently I concluded to use that 

 old filtrate for the purpose of testing the tenacity of life of the infectious 

 principle, and injected on January 12, 20 minims of the same by means 

 of a graduated hypodermic syringe into the cellular tissue, just behind 

 the fore-leg of pig No. 3. 



January 12 to January 25. — All three pigs appeared to be perfectly liealtliy, and liad 

 good appetite ; at least none of tliem exMbited any signa or symptoms of disease. 



