Landwirtschaftliche und forstliche Biologie. Parasiten, 155 



after a temperature of about 10" C. The leaves and cotyledons of several cruciferae 

 were found to be equally susceptible, and the same form of Cystojms .candidus could 

 grow on all the varietie's of radish (22 varieties were tried). the many varieties of 

 Brassica oleraces were found to be only very slightly susceptible, B. alba, on the 

 other hand, being susceptible to the Cystopus that occurs on the common radish. As a 

 result of experiments, it is concluded that temperature is a Controlling factor in the 

 spore germination of Cystopus. It is also believed that healthy radish plants are more 

 susceptible than sickly ones, a conclusion which might be explained by M. Cook's view 

 that the excess of tauuin in plants injured by fungi or iusects increases their degree of 

 immunity. Gates (London). 



■422) Welsford, E. L,, The morpholog-y of Trichodismus elefjans, gen. 

 et. sp. nov. Annais of Botany, Bd. 26, Heft 1, S. 239—242, 1912. 



A new geuus and species of Chactophoraccae (green Algae) is described, 

 parasitic on the water-fern Azolla. This alga, unlike Stigeoclonimn, reproduces 

 both sexually and asexually under the same environmental conditions, 



Gates (London). 



423) T. Betegh, L. (Fiume), Studien über experimentelle Tuberkulose der 

 Meeresfische. In: Centrabl. f. Bakteriologie, L Bd. 58, Heft. 6, S. 495-504, 1911. 



Fisch-, Blindschleichen- und Schildkrötentuberkulosebazillen können bei Meeres- 

 fischen typische Tuberkulose hervorrufen. Außer den strukturellen und biologischen Ver- 

 hältnissen sind die beiden letzteren Tuberkelbazillen also auch hinsichtlich ihrer Patho- 

 genität von den "Warmblütertuberkelbazillen verschieden. Seitz (Bonn). 



424) Maurer, 0., Bacteriological Studies on Eggs. In: Kansas Agr. Exp Sta. 

 Bul. 180, S. 3.S3— 396, 1911. 



Contains three papers on various phases of the general topic indicated by the title. 

 These papers are I. "The Bacteriology of Eggs and Egg Products with Special Refe- 

 rence to B. coli": IL "A Discussion of the Healthfulness of Frozen and Dessicated 

 Eggs". III. "Bacteriological Studies of Newly Laid Eggs". The third paper is the only 

 one of general biological interest. In it an attempt is made to learn the relation of 

 various physiological factors to the bacterial content of new-laid eggs. The chief results 

 are as foilows : 



Eighteen and one-tenth per cent of the total number of eggs analyzed showed bac- 

 terial growth at room temperature, while only 8,3 percent showed growth at blood tem- 

 perature. Of the infected eggs, 82 percent were infected in the yolk, 25,9 percent in 

 the white, and only 7,9 percent in both white and yolk. The bacterial content of eggs 

 nndergoes great seasonal changes, generally increasing with the rise in temperature. No 

 definite relation could be traced between the bacterial content of eggs and their hatching 

 qualities. No relation could be found between the age of the fowls and the bacterial 

 content of their eggs. No definite iufluence of a fattening ration upon the number of 

 eggs infected and upon their hatching qualities could be observed. Pearl (Orono). 



425) BussOQ, Br. (Graz, Hygienisches Institut), Ein Beitrag zur Kenntnis der 

 Lebensdauer von Bacterium coli und Milzbrandsporen. In: Centralbl. f. 

 Bakteriologie, I. Bd. 58, Heft 6, S. 505—509, 1911. 



Ein vor G^^ Jahren in destilliertes Wasser eingesäter Coli-Stamm hat während 

 dieser Zeit nichts von seinen Merkmalen eingebüßt. Aus an Seidenfäden angetrockneten 

 Milzbrandsporen entwickelten sich nach 17 Jahren lebenskräftige äußerst virulente Milz- 

 branballziden, deren Sporenbildung sich in gewissen Grenzen erhalten hatte. 



Seitz (Bonn). 



426) Bottomley, ^\, B., King's College, London, The root-nodules of Myrica GaU. 

 In: Annais of Botany, Bd. 26, Heft 1, S. 111—117, 1912. 



Nitrogen-fixing organisms are now known to occur not only in the roots of the 

 Leguminosae, but in Alnus, Elaeagniis, Podocorpus, Cijeas and Blyrica. The present 

 study of the root-nodules of Myrica shows that these nodules are modified lateral 

 roots, the young nodules branching to form Cluster nodules surrounded by rootlets which 

 grow out through the end of each brauch. 



Each nodule contains four zoues, (1) the apical meristem which grows out to form 

 a rootlet; (2) the 'infection thread' area; (3) the bacterial zone, which includes the cortex 



