324 THE FERMENTATION OF CHEESE. 



cheese, which, if it contains many holes of small size, is charac- 

 terised as " Nissler," and considered as inferior. Still, the other 

 extreme of immoderately large cavities is also undesirable. This 

 last condition reveals itself, in the course of its development, by 

 the bulging of "the surface of the ripening cheese, which, in par- 

 ticularly bad cases, is even split open. This malady, known as 

 inflation or puffiness, has already formed the subject of several 

 investigations, as a result of which both the cause of the'com- 

 plaint and a means of preventing and combating it have been 

 discovered. 



181. The Cause of Puffy ("Blown") Cheese. 



The naturally obvious hypothesis that pitting is due to the 

 gas-producing powers of microbes was experimentally confirmed by 

 H. WEIGMANN (VIII.) in 1890. Undoubted though it be that 

 inflation is also a result of microbial activity, it is, nevertheless, 

 equally undecided whether the malady is caused by specific fer- 

 ments, or only differs from normal pitting in degree, i.e. arises from 

 the same cause. 



Of the two possible methods of explanation here indicated, the 

 first is championed by ADAMETZ and FREUDENREICH (VI.) in par- 

 ticular. The latter in 1890 established, in the case of three 

 species of bacteria recognised as setting up inflammation of the 

 udder in cows, and named Bacillus Guillebeau a, b, c, after their 

 discoverer that when inoculated into fresh curd they produce 

 inflation and bad flavour. The fermentative activity and products 

 of these three microbes were minutely examined by A. MAC- 

 FAD YEN (I.) and L. NENCKI (L). The gas evolved by B. G. c. is 

 a mixture of carbon dioxide and hydrogen, their relative pro- 

 portions at the climax of fermentation being about 76 : 23, but 

 afterwards becoming so far modified that, at the close of fermenta- 

 tion, only 0.72 per cent, by volume of hydrogen is found in the 

 gas. To these three injurious organisms (pathogenic in cows and 

 goats) a fourth was soon afterwards added by FREUDENREICH (VII. ), 

 viz., Bacillus Schafferi (bacteriologically very similar to Bacterium 

 coli commune) which was first obtained as a pure culture from 

 "puffy" cheese, and subsequently also found in "Mssler" cheese. 

 Freudenreich consequently regarded this bacillus as the cause of 

 both these maladies in cheese, and explained its dual manner of 

 working by stating that puffiness is produced when the fresh 

 cheese curd contains comparatively few colonies of this bacillus, 

 at considerable distances asunder, but of large size, and therefore 

 capable of liberating much gas; whereas, 'on the other hand, 

 "Nissler" cheese results when the microbe is distributed abun- 

 dantly, as individual cells, throughout the ripening mass. 

 ADAMETZ (VII.) found in the milk and cheese of a Sornthal 

 dairy a fission fungus which he named Micrococcus Sorntlialii, 



