144 



hour's time there was not the faintest trace of any blue reaction, all of 

 the bacterial fragments remaining yellowish brown. Some unwashed 

 masses of bacteria, carefully removed from the surface slime of one 

 of these banana cultures, were now thrown into the beaker. Their 

 surface immediately blued, and in a few minutes each one of these 

 masses became deep blue throughout, forming a ver}' striking con- 

 trast to the 3^ellow stain in the washed particles. 



It may be that substances absorbed from the substratum into the 

 bacterial layer will account for all of the few. recorded cases of cellulose 

 reaction in the bacteria. This possible source of error is certainly 

 worthy of ver}" careful consideration. 



VITALITY. 



Length of Life in Culture Media. 



No special attention was given to this subject, but from time to time, 

 for various purposes, tubes of suitable culture media were inoculated 

 from old cultures. The results show that Ps. hyacintJu is not readily 

 destroyed by its own decomposition products. The nature and age 

 of the old cultures in which this organism was still alive are given 

 below: Feebly (litmus) alkaline potato broth, 24 da3^s; beef broth 

 neutral to phenolphthalein. with 5 per cent cane sugar, 32 days: mod- 

 erately alkaline beef broth, with 10 per cent cane sugar. 79 days: acid 

 (unneutralized) beef broth. 26 and 64 days: feebly (litmus) alkaline 

 slant agar, 24 days: nutrient starch jelly, 31 days: sugar beet. 52 days: 

 coconut, 59 days: white turnip, 41 and 80 days: radish, SO days: gel- 

 atin neutral to phenolphthalien, 38 days; gelatin alkaline to phenol- 

 phthalein, i. e.. —20 of Fullers scale, 156 da^^s: malic acid gelatin 

 (acidity +54 of Fuller's scale), with 10 per cent cane sugar, at temper- 

 atures ranging from 10^ to 25^ C, 174 days. In a potato culture 91 

 days old the organism was dead. It was also dead after 33 days in 

 a beef broth made feebly alkaline to litmus by sodium carbonate. 

 It was dead in 5 coconut cultures at the end of 2 ^xars; it was dead 

 on sugar beet after 2 years and 10 months; it was dead in 3 cultures 

 on agar (stock 527) after 17^ months. These results indicate that the 

 organism is fairly resistant, and also that it produces very little 

 organic acid. 



Ps. cainpestris^ Bacillus aniylovarus, B. carotncvrus. B. jji/oci/cuieiis 

 pericarditidis, and a green fluorescent germ which grows in the pres- 

 ence of thymol, and which was isolated by the writer from one of Dr. 

 Loew's tobacco infusions, svere all alive on agar (stock 527) after I7i 

 months. Ps. stewarti^ on the contrary, was dead (2 tubes). Ps. 

 phaseoU was also dead. All of these tubes were in the stock-culture 

 box, subject to the same degree of cold (temperature 5' to 16^ C), 

 moisture, and darkness. Under similar conditions Ps. camptstrls was 



