ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 521 



organism forms tubercles or swellings on the roots ; the amoebae, he 

 finds, send out protoplasmic threads, which penetrate through the cell- 

 wall from one cell into another. The means by which infection takes 

 place is by the entrance of air amoeba into a root hair. 



He d born, K. — Nagra nyare fynd af svenska myxomyceter. (New records of 

 Myxomycetes.) Svensk. Bot. Tidskr., iv. (1910) pp. 94-5. 



See also Bot. Centralbl., cxvi. (1911) p. 593. 



Schizophy ta. 

 Schizomycetes. 



Absorption Phenomenon in Microbes.* — M.W. Beijerinck has shown 

 that when Oidium lactis is sown on an agar plate containing glucose and 

 mono-potassium phosphate, no growth occurs. If a crystal of urea be 

 then placed on the surface of the medium, a growth of Oulium appears 

 all round it. The urea supplies the element necessary for the growth of 

 the organism. The auxanogram obtained does not show an ordinary 

 diffusion picture with gradual tailing off at the margins, but is almost 

 sharply cut, a slight thinning at the edge being only with difficulty 

 perceptible. A similar- result is obtained by interchanging the glucose 

 and the urea. There are three phases in this phenomenon : a period of 

 diffusion of the urea through the medium, a period of absorption by the 

 micro-organisms, and a period of growth during which the urea rapidly 

 disappears. 



Fermentation of Sugars by Bacteria.f — Y. Mendel has carried out 

 researches upon the conditions under which bacteria cause fermentation 

 of sugars, and gives in tabular form the results of an extensive series of 

 estimations, for various sugars and various organisms, of the amount of 

 gas produced, the proportion of carbon dioxide to hydrogen in this gas, 

 the amount of acid, and the ratio of fixed to volatile acid. The sugars 

 selected for investigation were glucose, maltose, and lactose. Most of the 

 experiments were performed with Bacillus coli and allied organisms. The 

 author found that fermentation was most active in solutions containing 

 6-10 p.c. of sugar, a rather higher degree of concentration than that in 

 favour with previous workers. 



Methods of Agricultural Bacteriology. :f — Th. Rerny and G. Rosing 

 have investigated a number of important matters in connexion with the 

 bacteriological examination of soil. They set themselves to determine 

 the degree to which a soil is capable of destroying peptone, and the 

 power which it possesses of splitting up complex nitrogenous substances. 

 They found that peptone was more readily broken up than blood-albumin 

 or gelatin. They then investigated the effect which the chemical compo- 

 sition of the soil had upon the course of peptone disintegration, and 

 their experiments showed that the addition to the soil of salts containing 

 potassium, magnesium, phosphoric and sulphuric acids, greatly increases 

 the peptone-disintegrating power of the bacteria. A similar, though less 



* Centralbl. Bakt., 2te Abt., xxix. (1911) pp. 161-6. 

 t Centralbl. Bakt., 2'e Abt., xxix. (1911) pp. 290-330. 

 \ Centralbl. Bakt.,2te Abt., xxix. (1911) pp. 36-77. 



