656 



SCIENCE 



[N. S. Vol. XXVIII. No. 723 



in upper Georgia. A single individual of a 

 noisy congregation of males had the unmis- 

 takable trill of the common toad, but short 

 and decisive like the Fowler's song. It was 

 a perfect combination of the notes of both. 



Wherever I have found this toad — in cen- 

 tral and southern New England, around 

 Washington, D. C, and in northern Georgia — 

 it has been the only common form. Through- 

 out the region of Jackson and Gwinnett 

 counties of northern Georgia this toad is ex- 

 tremely common. Whether or not its range 

 extends into the central or southern portions 

 of the state, I have not determined. It is 

 evident that Bufo fowleri occurs abundantly 

 in much of the territory east of the Ap- 

 palachian Mountains, and is far from being 

 an uncommon or local race or species. 



H. A. Allaed 



Btjbeau of PijAnt Industet, 

 Washington, D. C. 



a preliminary note on a group of lactic acid 



bacteria not previously described 



in america 



Various bacteria forming acid in milk have 

 been described. The organisms most frequent- 

 ly met and which are of the greatest economic 

 importance are those belonging to the group 

 represented by Streptococcus lacticus (Kruse) 

 or the Bact. lactis acidi of Leichmann. This 

 group is characterized by the small amount of 

 acid which the organisms are able to produce 

 in milk. The milk acted upon by pure cul- 

 tures rarely shows an acidity exceeding one per 

 cent. The limiting factor is apparently the 

 formation of free lactic acid, the organisms 

 being unable to grow in the presence of free 

 acid. As numerous investigations have 

 shown, the amount of acid produced varies 

 with the composition of the milk. Milks high 

 in casein and ash constituents develop a 

 greater amount of acid under similar condi- 

 tions than do milks whose casein and ash 

 content is lower, because these substances com- 

 bine with the acid formed. 



Freudenreich, in Switzerland, has described 

 a class of lactic-acid-forming bacteria which 

 are able to produce much greater amounts of 

 acid in milk than the organisms of the 



Streptococcus lacticus group. This group of 

 high acid-forming organisms has been brought 

 into prominence recently by the work of 

 MetchnikofE and others on the fermented 

 drink yougurt which is prepared from milk. 

 The organisms found in this type of fer- 

 mented milk are characterized by the produc- 

 tion of large amounts of acid, three per cent, 

 and over, by the high optimum temperature 

 for growth, 42-45° C., by growing only under 

 certain narrow conditions on artificial media, 

 and by their morphology, being large bacilli. 

 In all these the organisms from yougurt agree 

 with those described by Freudenreich. 



It has not been thought that such organisms 

 are widely distributed. Indeed some writers 

 have asserted that this type was peculiar to 

 the country to which yougurt is native, 

 Bulgaria. Within the last few months it has 

 been found that organisms whose character- 

 istics are similar to those found by Freuden- 

 reich in Swiss cheese and to those found in 

 yougurt are of common occurrence in this 

 country. 



If a sample of mixed milk is placed in a 

 tightly stoppered bottle and incubated at 

 37° C. the acidity rapidly reaches one per 

 cent., due to the growth of Streptococcus 

 lacticus. The acidity then continues to in- 

 crease slowly until at the end of two to three 

 weeks it reaches 2.5 to 3 per cent. The flora 

 at first made up almost wholly of the small 

 diplo-bacilli changes, through the appearance 

 of long slender bacilli, which increase in num- 

 ber with increasing acidity. 



In cultural characteristics and in bio- 

 chemical reactions, the organism isolated is 

 apparently of the same group as those of 

 Freudenreich and the bacteria in yougurt. 



As far as the writer is aware, this type has 

 not previously been found in this country, 

 although it is of wide distribution, and has 

 been present for years. Milk bottled in 1902 

 was recently opened, and showed an acidity of 

 over 3 per cent. A detailed study of the dis- 

 tribution and characteristics of the organism 

 is being made. 



E. G. Hastings 



Wisconsin Experiment Station 



