BUREAU OP ANIMAL INDUSTRY. 673 



any surface growth. Later observations showed that if a more alka- 

 line nutrient gelatine he used the growth is far more vigorous; the 

 deep colonies are much larger and the surface growth abundant 

 (Plate VI, Figs. 4, 5). It presents either as a compact convex pearly 

 disk or button, or as a very irregular flat patch, sending out ragged 

 prolongations over the surface of the gelatine. 



This microbe grows upon blood serum from the cow. On the sur- 

 face the growth is very thin, scarcely visible. In the needle track a 

 dense opaque mass forms. On the condensation liquid in the bottom 

 of the tube a whitish, brittle membrane is present. Repeated efforts 

 to induce growth on potato have thus far failed. In milk its multi- 

 plication is not very great when compared with the other microbes. 

 It is capable to a certain extent of multiplying in tubes from which 

 the air has been exhausted and in whicn the ordinary saprophytes 

 remain dormant. When exposed to a temperature of 58° C. for fif- 

 teen minutes it is invariably destroyed. This is true of the bacteria 

 taken directly from the animal as well as of those in liquid cultures. 

 This microbe is easily killed by drying, three days being sufficient, 

 whether it is taken from cultures or from the tissues of the dead 

 animal. 



Upon sterilized cover-glasses a drop from a liquid culture two days old is allowed 

 to dry under a plugged funnel. On the third day a tube of beef infusion, into 

 which one of these cover-glasses had been dropped, remained clear. On the sixth, 

 seventh, and ninth days tubes were inoculated in the same way, which also re- 

 mained clear. 



Exudate from tlie peritoneal surface of the liver of a rabbit which died from in- 

 oculation was dried on cover-glasses and tested in the same way. The exudate con- 

 tained immense numbers of microbes. One tube inoculated after four hours' dry- 

 ing, two after one day, and two after two days became opalescent and were found 

 pure cultures. Two inoculated on the third, fourth, and fifth day remained clear. 



The multiplication in ordinary drinking water was tested as de- 

 scribed for the hog-cholera bacteria. The latter, very hardy, as the 

 experiments showed, remained alive in large numbers for months. 

 The microbes under consideration showed themselves almost inca- 

 pable of living and multiplying in such water. In fact, it is very 

 probable that many are destroyed in being transferred into it from 

 nutrient media. 



On November 20 a tube containing sterilized Potomac drinking water was inocu- 

 lated from a culture two days old. A plate culture immediately prepared to deter- 

 mine the number of germs transferred was lost by accident. Judging from preced- 

 ing experiments, there could not have been less than 50,000 in l^-^ of the water. 

 Plate cultures containing .1" of water were made two and three days after inocula- 

 tion. Nothing grew upon either plate. On the sixth day a tube of beef -infusion 

 peptone was inoculated from the water. The Uquid remained clear. 



On November 27 a tube containing sterilized Potomac drinking water was inocu- 

 lated from a liquid culture of the microbe twenty-four hours old, A plate culture 

 made immediately after the inoculation showed two days later that each cubic cen- 

 timeter of the water contained after inoculation about 140,000 microbes. After 

 standin<; for two days at a temperature of 22° to 25° C. a plate culture made with 

 about ^,tt'% which should have contained at least 500 colonies, showed none what- 

 ever. December 6, nine days after inoculation, i'='^ was added to a tube of beef in- 

 fusion peptone. On the following day this tube was turbid and contained the mi- 

 crobe only. Hence a few individuals were still alive on the ninth day. A plate 

 culture was made from the same water twenty-four days later by adding i'^'^ to the 

 gelatine before pouring it upon the plate. No colonies gi-ew. Finally a tube of nu- 

 tnent liquid, to which i" was added on the twenty-seventh day, remained clear. 

 Hence all the microbes were practically dead before a month had passed, and the 

 great majority perished, without doubt, a few days after being mixed with the 

 water. 



43 AG— '86 



