154 MICRO-ORGANISMS AND FERMENTATION. 



the cells formed by division may remain clumped together, 

 caught in the slime secreted by the cells, and thus more or 

 less cubical groups are constituted, which sometimes have a 

 certain resemblance to corded bales of goods. On solid 

 substrata, on the contrary, the growth of many of these 

 species breaks down rapidly into single cells, or else remains 

 grouped in clusters of two and four. The harmful kinds 

 occurring in beer, which belong to this group of bacteria, are 

 really only known with division in two planes, and the pro- 

 duction of regular shapes (diplo- and tetracoccus), whilst the 

 larger clusters are composed of irregularly massed cells. Until 

 something further is known about them, these species must, 

 therefore, be counted in the group which shows division in 

 two planes (Pediococcus, Micrococcus, and Merismopedia). A 

 similar behaviour is shown by Sarcina rubra, discovered in 

 red milk by Menge, which in milk only displays the micro- 

 coccus form. The sarcina form is known in broth-cultures. 



The many species of Sarcina that have been described can 

 give differently coloured colonies on gelatine ; white or greyish 

 colonies are formed by S. alutacea, isolated by Gruber from 

 leaven, which liquefies gelatine. This is also the case with 

 Lindner's S. Candida, found in the water reservoir of a brewery. 

 Yellow colonies are formed by the widely distributed S. flava 

 which has been found in leaven, beer, and elsewhere. It 

 forms both regular packets and irregular masses of cells. On 

 gelatine it gives small round colonies, which gradually liquefy 

 the gelatine, and on hay infusion it forms a film with a strong 

 development of packet shapes. S. aurantiaca forms on gelatine 

 orange-yellow, liquefying colonies, but develops the typical 

 sarcina form only in hay infusion and plant decoctions. It 

 gives a dark bluish-green colouration with sulphuric acid. S. 

 casei, discovered by Adametz in cheese, forms pale yellow, 

 liquefying colonies with concentric rings, and coagulates milk. 

 Adametz also found S. butyrica in cheese ; it forms a yellowish- 

 white colony on the surface of stab-cultures in potato gelatine, 

 but dark liquefying colonies in plate-cultures. S. lutea always 

 forms regular packet shapes, and gives on gelatine lemon- 

 yellow, non- or only feebly liquefying colonies. Brown 

 colonies on gelatine are given by 8. acidificans discovered by 



