1922] 



ROSEN — A BACTERIAL DISEASE OF FOXTAIL 369 



done through filter-paper in contrast to glass wool which, when 

 used as a filter, did not absorb these substances. Since the filter- 

 ing done by the writer, and as commonly practiced, is through ab- 

 sorbent cotton, it seemed desirable to test the effect of glass wool 

 as compared with cotton on the growth of the foxtail organism. 

 Using nutrient agar, adjusted to P H 7, as the medium no difference 

 in growth was detected, and in another series in which it was 

 desired to obtain a comparison between distilled water and tap 

 water in a medium of nutrient agar each kind of medium was 

 divided into 2 parts, 1 filtered through cotton and the other 



through glass wool. No difference in growth was evident either 

 when tap water was contrasted with distilled water or when 

 glass wool was used instead of cotton. In still another series, 

 using nutrient agar as the medium, the 2 different filtering agents 

 were used and part of the medium sterilized by the intermittent 

 process in the Arnold sterilizer and the other part sterilized in 

 the autoclave at 15 pounds pressure for 30 minutes. It was 

 thought that if any "growth accessories" or "hormones" were in- 

 volved a difference in sterilizing temperatures in conjunction 

 with different filtering agents might show a difference in growth, 

 but no difference was observed. It may perhaps be concluded 

 that the foxtail organism does not respond to "growth accesso- 

 ries" although further work is necessary before this is accepted. 

 Loeffler's blood serum. — Growth restricted, whitish, glistening, 

 filiform, slightly raised, and smooth ; the medium was not lique- 



fied. 



Lima bean agar slants. — Growth in this medium was excellent; 



it was fully as good, if not superior, to any other medium tried, 

 and bears out the suggestion made by others of making greater 

 use of vegetable media in the study of bacterial pathogens. (The 

 medium consists of 100 grams of dry lima beans, 15 grams of 

 agar, and 1000 cc. of distilled water.) The beans were cooked 

 until they readily fell apart and were strained through cheese- 

 cloth, the cloth being squeezed so that all the available liquid 

 was recovered. (The medium as it finally appeared was rather 

 turbid.) At 30° C. there was marked growth in 48 hours; it 

 was raised, glistening, whitish, filiform, and there was no color- 

 less zone or precipitate (P H value not tested). As the culture 

 became several days old a slight pinkish color developed in the 

 smear, which was particularly noticeable at the base of the slant. 



