344 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Chemical analysis of numerous samples show that its sharp taste is 

 due to the presence of hictic acid, whilst small quantities of alcohol were 

 also noted. Five varieties of micro-organisms, and no more, were invari- 

 ably detected in the fresh Lehen. viz.a stout bacillus arranged in chains 

 of 5 to 10 elements, Streptobacillus lebenis ; a slender bacillus always 

 occurring singly, Bacillus lebenis ; a diplococcus resembling the gono- 

 coccus in morphology, Diplococcus lebenii ; an ovoid-celled yeast, Sac- 

 charomyces lebenis ; and another yeast with elongated cells, Mycoderma 

 lebenis. All these organisms stain by Gram's method. The yeasts were 

 readily isolated by means of serial cultivations on agar, hut on account 

 of their luxuriant growth the bacilli and the coccus could not at first be 

 obtained in pure culture ; but by planting fresh Lehen in freshly 

 sterilised milk and incubating anaerobically in Pasteur's tubes at 37° C. 

 f.»r 24 hours through several generations the yeasts, being strict aerobes, 

 were completely destroyed, and the bacilli were then readily isolated by 

 means of aerobic cultivations upon glucose agar, and the diplococcus 

 \ipon 2 p.c. lactose agar. 



These five organisms were then studied in detail and their morpho- 

 logical and biological characters determined, the characteristic features 

 of the bacilli and the coccus, all facultative anaerobes, heing their selec- 

 tive preference for sugar media, — glucose or lactose heing essential to 

 their growth. 



Finally, by planting these five organisms in freshly sterilised milk, 

 in the following order, first the two blastomycetes together with the B. 

 lebenis, and after a short interval to allow of their development, adding 

 the streptobacillus and the diplococcus, the authors were able to produce 

 a preparation of milk which was identical in appearance, taste, and 

 chemical composition with true Egyptian Leben. 



Ri6t and Khoury conclude that the method of action of these organ- 

 isms is as follows. The streptobacillus and the diplococcus coagulate 

 the milk by the combined action of the lactic acid and the rennet that 

 they produce, whilst the streptobacillus renders the milk fermentable 

 and enables the two blastomycetes to elaborate the alcohol and also some 

 ill-defined aromatic compounds. The B. lebenis, although probably 

 aiding the streptobacillus and the diplococcus in their work, does not 

 appear to be absolutely essential to the process. 



Acid-fast Bacilli.*— Dr. A. Mocller emphasises the fact that all 

 acid-fast bacilli are not necessarily tubercle bacilli, and describes and 

 compares the various " named " species of acid-fast organisms. 



The Leprosy bacillus, first described in 1877 hy Hansen, closely 

 resembles the tubercle bacillus in its staining reactions and also in 

 morphology, but individual bacilli are slightly shorter, while cultivations 

 of the bacillus upon artificial media have not yet been obtained. 



The Smegma bacillus, found hy Tavel and Alvarez in 1885 in normal 

 preputial secretion, &c, resembles the tubercle bacillus in that it is acid- 

 fast, but differs in being, usually, less alcohol-fast: still, it is quite 

 possible to confuse the two organisms in a secretion such as urine. 

 Morphologically it often resembles a diphtheria-like hacillus found in 

 smegma, but which is not acid-fast. No cultivations of the Smegma 



• Centralbl. Bakt., V Abt, xxx. (1901) pp. 513-23. 



