( 19 ) 



They are always immotile, no-spore forming bacteria, which bear 

 drying very well and which, by heating to f>5 or 75° ('., in which 

 they just remain alive, while these temperatures are deadly to most 

 other non sporeproducers, may lie separated from these ("lacticisation"). 

 They require for nitrogenfood peptones, such as are found in milk, 

 malt extract, or other juices of plant- or animal origin, and for carbon 

 food certain sugars, which may differ for different species. They do not 

 peptonise proteids and, thus, do not liquefy gelatine: the secreted lactic 

 acid can dissolve a certain quantity of caseine, but chemically this 

 substance remains unchanged. These circumstances regulate their 

 distribution in nature, where they are by no means general, bul may 

 rapidly multiply, especially under the influence of man. They are, 

 however, found in the soil and can, l>\ methods mentioned below, 

 he accumulated and cultivated in a condition of pureness. 



They are always more or less distinctly microaerophiloiis. some 

 species or varieties can, however, grow very well at the air: other 

 forms cannot and behave as real anaërobics. Access or absence of 

 air is commonly of no consequence to the acid formation, lint in the 

 yeast industry a specie-- is used, which at full atmospheric pressure 

 produces no acid, and in the dairy industry are also forms which 

 di>play the same property. 



Always, even on good nutrient media, to which belong in particular 

 maltextracl agar, and milk- or whey-agar, the growth of tin' colonies 

 remains limited, especially if the air and the produced acid can act 

 simultaneously. If the acid i- neutralised by chalk the growth ofthe 

 colonies at the air may also become important. Vet. in most cases, 

 the recognition of these ferments may repose on the smallness of 

 their colonies compared with those of other bacteria. 



Catalase is constantly absent, and hereupon an excellent diagnosis 

 can he based, for which it is only necessary that a culture plate, on 

 which all kinds of bacteria may occur, he flowed with strongly 

 diluted hydrogensuperoxyd which is by all microbic species, except 

 the lactic acid ferments, indifferently whether they belong to Lacto- 

 coccus, Lactobacillus or Laclosarcina, changed into a scum of little 

 oxygen bubbles. 



Even the lately described 1 large celled Sarcina, which in conse- 

 quence of continued research 1 now consider as identic with the 

 stomach sarcine (Sarcina ventriculi), ami whose acid producing 

 power is very slight, — i. e. 3 c.c. of normal acid per 100 c.c. of 



M These Proceedings 2o Februari 1905. Archives Néerlandaises T. 1 and 2. T. 11, 

 p. 200, 1906. 



2* 



