16 



From this table it would appear that the limits of growth for Ps. 

 hyacinthi^ under the conditions mentioned, lie between — 20 and — 40 

 on the alkaline side (probably near — 35) and somewhat beyond +30 

 (probably near +40) on the acid side. For a long time I was in 

 doubt as to whether any growth had taken place in +30, and it is not 

 at all improbable that with the introduction of a lesser number of 

 germs — e. g., a loop from a fluid culture — no growth would have taken 

 place. 



At the same time duplicate tests were made of a number of other 

 bacteria and some of the results obtained are shown in the following 

 table. Here, again, the tests were insufficient in number to bring 

 out all of the peculiarities of the organisms. For instance, there should 

 have been broths with intermediate grades of alkalinity and acidit}^, 

 and for two of the organisms, B. pyocyaneus jjericarditidis and B. 

 coli, the series should have been extended on the alkaline side to at 

 least — 100. I have partially compensated for this by stating how soon 

 the clouding appeared in certain of the fluids. In case of Ps. stewarti 

 and B. coli the experiments should have been repeated in the +60 

 broth, since the growth was in any event feeble, and I was at times in 

 doubt as to whether there had been any whatever. The — 80 bouillon 

 was inoculated June 13 with 2 mm. loops from fluid cultures 2 days 

 old. 



