1897] MICROSCOPICAL JOURNAL. 331 



g-ermination the young- plants having- passed through cul- 

 tures containing these organisms. Nor were his results 

 with other pathogenic saporphytic organisms more favor- 

 able where onions or hyacinth bulbs were used, or when 

 cultures were inoculated into plants above ground. Var- 

 ious minerals speedily destroyed the organisms. It is not 

 probable therefore that pathogenic bacteria are ever taken 

 up by the roots of plants. 



Appropriation of Free Atmospheric Nitrogen. — Nitro- 

 gradsky is well-known on account of his extended and 

 thoroug-h studies of micro-organisms in connection with 

 the subject of nitrification. He has now given us the result 

 of his studies on the above topic. In isolating these organ- 

 isms he used what is by him termed the "elective" method 

 of isolation. In this special case a culture medium was 

 employed that was free from all combined nitrogen. It 

 was made up as follows : 



Distilled water, lOOOcc; 20-40 gr. dextrose; 1 gr. potas- 

 sium phosphate; 0.5 g-r. mag-nesium sulphate; 0.01-0.02 gr, 

 potassium chlorate, sulphate of iron, sulphate of mang-anese. 

 This culture medium was then inoculated with garden 

 earth. Most of the cultures soon showed evidence of 

 butyric acid fermentation. Gas bubbles appearing in the 

 immediate vicinity small masses floa:^ing in the medium. 

 These masses somewhat resembled Kephir grains. This 

 fermentation continued till all of the sugar was used up. 

 After this fermentation, mould developed on these white 

 grain-like masses, followed by algae. It appears that this 

 medium at first wholly unsuited for higher plants because 

 of the absence of nitrogen was made sutiable when appro- 

 priation of nitrogen by bacteria had taken place. The 

 Kephir like masses consisted of a species of Clostridium 

 to which he has given the name of C. pasteurianum, and 

 two kinds of bacteria forming threads. The interesting 

 details cannot be given here. Suffice it to say that this 

 Clostridium is capable of obtaining- nitrogen from the 

 atmosphere, which is found in the medium in part as solu- 

 ble inorganic nitrogen, but mostly as insoluble organic 



