47 



(2) Stock 8(Mk- was lui old, ])artially evaporatedflask of 286d lirouoht 

 ])a('k to its original volume by adding distilled water. Its aeidit}' 

 was +^0; i. e.. exactly SO c. c. of y NaOII would have Ixmmi reciuired 

 to neutralize 1 liter, using phenolphthalein as the indicator. Stock 

 3001) was a portion of 3()0c diluted with an equal ))ulk of distilled 

 water, so that its acidity was reduced to +40. Stock 30()a consisted 

 of a portion of 300c diluted with twice its bulk of distilled water, the 

 acidity being consequent!}^ reduced to al)out +27. Three tul)es of 

 each stock were inoculated from an alkaline beef-broth culture 11 days 

 old. All of the tubes were kept together in feeble, diti'used light, in 

 well-plugged tubes of resistant glass, at I'oom temperatures of 20^ to 

 23'^ C. Two of each set wx're inoculated with large loops, the third 

 with a tiny drop from the tip of a needle. 



Result. — In 300c there was no growth whatever (21 days). In 30()b 

 growth was nuich retarded, the fluid remaining clear for S da^'s, and 

 pr()})al)ly for a nuich longer period. On the twenty-first dav, when 

 next examined, the two tubes inoculated b}^ loop were feebly clouded, 

 and showed a moderate amount of ^^ellow precipitate. There were 

 also (|uite a good many large yellowish flecks (zoogkere), on the w^alls 

 and floating in the fluid. In the tube inoculated by needle the cloud- 

 ing was iK^ry feeble, there was only a dig Jit precipitate, and there were 

 no zooglcjea?. On the twenty-flfth day the fluid in the needle culture was 

 neutral to sensitive neutral litmus paper, while in the loop cultures it 

 had become feebh^ alkaline. In 300a clouding was visible on the sixth 

 day in the loop cultures, and on the eighth day in the needle culture. 

 Here also growth was retarded, but not so long as in 300b; e. g., on 

 the twenty-first day the tube of 300a, which was inoculated by needle, 

 was about twice as cloud}^ and contained ten times as much precipi- 

 tate as the tubes of 300b, which were inoculated by loop. The organ- 

 ism changed the fluids from acid to alkaline, and in the end (55 davs) 

 all of the cultures were much alike. 



(3) The last experiment was repeated, more attention })eing paid to 

 the time of first clouding in 300b. Each tube contained, as usual, 10 

 c. c. of broth, was tightly plugged, was inoculated wdth one loop {oese 

 2 mm. in diameter) from an alkaline beef broth culture 12 da3\s old, 

 and was set away in feeble light at room temperatures of 19^ to 26° 

 C. (mostly 20^ to 21° C. during the first 6 days). 



Rei<ult. — In 300a clouding was first visi))le on the sixth day, but was 

 then very feeble. In 300b the fluid remained perfectly- clear for 19 

 days. On the twenty-sixth day, a\ iien next examined, it was feebly 

 clouded. In 300c there was never an}- growth (26 days). 



Ps. carnjjestris^ Ps. p/uiseoli, and BacillKs aniylovoruH also refused to 

 grow in 300c. On the contrary, Ps. stewarti^ inoculated from a solid 

 culture, grew in it for a long time and very luxuriantly^ although 

 clouding did not appear until the eighth day. 



