Microbiology. — "Oidiiun lactis, the millaaouhl, and n simple 

 method to obtain pure cultfwes of anaerobes by means of it." 

 Bj Prof. Beijerinck. 



(Communicated in the meeting of February 22, 1919) 



The mail}' methods recommended for Ihe pure culture of anaerobes, 

 — whose multitude proves that none of them quite satisfies the 

 investigators. — maj be distinguislied in chemical and biological. 

 As to the former, of which Novy's exsiccator method is certainly 

 the best, everything has l)een trierl. This cannot be said of the bio- 

 logical methods based on the use of living organisms in particular 

 aerobic microbes for the removing of the oxygen. P'or myself only 

 after using the milkmould to that end I have obtained results worth 

 fixing once more the attention on it. 



Some chief points from the life history of Oidium iactis important 

 for expei'iments with this species may precede; a complete des- 

 cription is not necessary here. 



Properties of the niilhnould. 



The milkmould possesses a number of properties which render it 

 very fit for experiments in relation to re8j)iration, nutrition, growth 

 and sj'mbiosis. It unites the character of the moulds to that of the 

 yeasts, in particular with regard to the growth in and upon the sub- 

 strate which takes place without being accompanied by fei-mentation, 

 as also without the formation of conidia which curi-ents of air might 

 spread. Within the substrate the long-celled mycelium is found, on 

 the surface the chains of conidia which, even when extending free 

 in the air, cohere and never contaminate the environment as moulds 

 may do. 



It is easilj' obtained. A rich growth results when market milk 

 is left a few days in an open glass in a warm room ; the milk 

 then always covers with an Oidium film. Lactic acid ferments also 

 develop and by their production of acid further the growth of 

 Oidium, whilst they themselves are favoured in their development 

 by Oidium, bec£ttise it oxidises Ihe lactic acid to carbonic acid and 



