2026 Journal of Applied Microscopy 



CURRENT BACTERIOLOGICAL LITERATURE. 



H. W. CONN, Wesleyan University. 



Separates of Papers and Books on Bacteriology should be Sent for Review to H. W. Conn, 

 Wesleyan University, Middletown, Conn. 



_ ., , , ^^ , ,. , ., 1.C- t_ The author has given a valuable con- 



Beiierinck. Ueber oligomtrophile Microben. ^ -i ^- ^ ^u ui r 



Cent. f. Bac. li. Par. II. 7; 561, 1901. tnbution to the problem of nitrogen 



assimilation. He has coined the word 

 oligonitrophile to refer to micro-organisms which are capable of living in a medium 

 containing very little combined nitrogen, and are themselves able to assimilate 

 free atmospheric nitrogen. One or two species of such micro-organisms have 

 previously been described, but the author discovers and describes certain new 

 species with new properties. The most unique feature of his contribution is the 

 fact that both chlorophyll holding plants and colorless plants are capable of 

 assimilating nitrogen. Among the first stand certain species of the Cyanophyceae 

 group. These he studies by inoculating garden earth into flasks containing 

 solutions prepared from chemicals, but containing no nitrogen, and carefully 

 studying the growth of the micro-organisms. The chief plants which have this 

 power belong to the species Anabcena and Nostoc. To find that these organisms 

 are capable of assimilating free atmospheric nitrogen, is a new contribution to 

 knowledge. The author, however, does not give any chemical tests to prove 

 that there is actually an increase in the amount of combined nitrogen in the solu- 

 tions. The rest of the paper is devoted to a study of the colorless organisms, of 

 which he finds two new species of bacteria capable of assimilating free nitrogen 

 and belonging to a new genus. This new genus the author names Azotobacter. 

 It differs from those previously described in not producing spores. Two species 

 of the genus are found, one living in garden earth, and the other is found in canal 

 water. Both of them are motile organisms in their young condition, and neither 

 produces spores. In each case the organisms are capable of living in solutions 

 containing practically no nitrogen, and grow best under these conditions, assimi- 

 lating atmospheric nitrogen. As a source of energy they are capable of using a 

 large variety of carbon compounds. It is a curious fact, however, that when 

 cultivated in pure cultures, they may grow luxuriantly in the presence of a con- 

 siderable quantity of combined nitrogen, differing thus from some of the other 

 nitrogen assimilating bacteria. 



To this same general group of organisms, which he calls oligonitrophiles, the 

 author classifies the bacilli which produce the tubercles in the roots of legumes. 



H. w. c. 

 Sullivan, M. X. Some Experiments with 



Synthesized Media. Abstract of paper read Pasteur, Cohn and Others recognized 

 at 3d Ann. Meet, of Soc. of Am. Bact. ^^at some bacteria can secure their 



carbon, hydrogen, oxygen and nitrogen from simple compounds. This is to be , 

 expected from the close relationship of the bacteria to other plants. Recently 

 the question of simple synthesized media has received some attention from 

 Muntz, Jordan, and de Schweinitz. Since Pasteur, however, little use has been 

 made of media other than those made of meat-infusion and peptone with agar or 

 gelatin as a base. Meat-infusion and commercial peptone vary so widely in 

 their chemical composition and in their nutrient value, that media composed of 

 these substances are practically of no use in the study of pigment of antitoxin 

 production, or in the study of bacterial metabolism. 



Analysis of standard bouillon shows such small amounts of albumoses and 

 peptones that it appears as if we might neglect the meat-infusion entirely, or at 

 least replace the peptone by a non-nitrogenous, non-albumenous body. 



On medium (A), consisting of water 100 grams, Witte's peptone 5 grams, 



