I. Crude cultures of bacillus oligocarbophilus. 



Bacillus oligocarbophilus is obtained by the following accumulation experiment, 

 which, because of the purity of the thereby resulting vegetation, may be called a 

 perfect accumulation experiment^ 



Into a large Erlenmeye r-flask a thin layer is introduced of a nutrient liquid 

 of the same composition as used for the water culture of higher and lower green 

 plants, but with alkaline instead of acid reaction. 



One takes for instance: 



Distilled water 100 



Kaliumnitrate o.oi to o. i 



Dinatriumphosphate 0.02 



Mineral solution* i drop. 



This mineral solution* contains in one drop: 



8 Mgrms MgSO* . 7 H*O 



0.05 ,, MnSOi . 4 HaO 



0.05 FeCb . 3 HsO 



If from this liquid nitrogen, phosphor, kalium or magnesium is left out, special 

 experiments have proved, that no, or but an insignificant growth is obtained. As to 

 the necessity of the likewise added elements sulphur, manganese and iron, there still 

 exists some doubt. 



The inoculation is made with a not too small quantity of garden-soil, the flasks are 

 closed with a cotton plug, or with filter paper, without impeding the entrance of air 

 by diffusion, and the culture is left in the dark at 23 25 C. After two or three weeks, 

 the fluid, which itself remains perfectly clear, is seen to cover with a thin, white, or 

 feebly rose-coloured, very dry film, difficult to moisten, and macrdscopically resem- 

 bling a My coder ma- film, but consisting of minute bacteria, microscopically often invi- 

 sible without staining, and sticking together by a slimy substance. This is Bacillus 

 cligocarbophilns. 



The growth of the film continues for months, whereby a considerable accumula- 

 tion of organic carbon may be observed, which is not only visible to the naked eye by 

 the vigorous bacterial growth, but can also be proved by direct weighing, and by a 

 comparison of the permanganate numbers found before and after the experiment, of 

 which some instances are given below. 



As there is reason to admit that our bacterium is generally distributed in garden- 

 soil, and was without doubt always present in the crude material used for the inocula- 

 tion, the failing of the film-formation in some of the flasks must necessarily result 

 from the chosen culture fluid being less favorable to the feebler germs and not allo- 

 wing their growth. So we observed that water, distilled in a copper apparatus, caused 

 many more failures than when distilled in glass; we therefore afterwards always used 

 the latter. In other cases monads, which immediately devoured the bacteria, were 

 cause of the failure ; by transfers and by the use of pure cultures, these voracious 

 organisms could be rendered harmless or removed. When the distilled water is repla- 

 ced by tap-water, the number of flasks remaining without growth after inoculation 

 with the same quantity of garden-soil is much smaller. 



