No. 3, July, 1921] PHYSIOLOGY 



321 



2185. Pringsheim, E. G. Uber die gegenseitige Schadigung und Forderung von Bakterien. 

 {The mutual injury and stimulus between bacteria.] Centralbl. Bakt. II Abt. 51: 72-85. 

 1920.— Methods are suggested for the study of the effects of 2 cultures of bacteria growing 

 together. Bacillus mesentericus vulgatus on the same plate with B. diphtheriae inhibits the 

 growth of the latter, so that even 8-10 colonies of the former will repress entirely the growth 

 of B. diphtheriae. In addition to the injurious action B. mesentericus vulgatus also exerts a 

 stimulating action on B. diphtheriae as indicated by the formation of giant colonies of B. diph- 

 theriae in the zone of influence of the former. The substance produced by B. mesentericus vul- 

 gatus is a thermolabile poison which stimulates in small doses and injures in large ones. Other 

 spore formers of the hay bacillus group, 8 of which were tested, did not exert the same antago- 

 nistic action. B. coli and B. paratyphosus A were not affected by B. mesentericus vulga- 

 tus. The action of various bacteria on B. influenzae, on the gonococcus, and on certain 

 anaerobes was also studied. — Anthony Berg. 



2186. Rockwell, G. E., and C. F. RIcKhann. The growth of the gonococcus in various 

 gaseous environments. Jour. Infect. Diseases 28: 249-258. 1021.— This is a study of the 

 growth of Gonococcus under the influence of hydrogen, oxygen, and carbon dioxide. It is 

 suggested that the fact that bacteria are aerobic, partial tension, anaerobic, or facultative 

 in their respiratory requirements is an expression of their previous gaseous adaptation.— 

 Selman A. Waksman. 



GROWTH, DEVELOPMENT, REPRODUCTION 



2187. Crocker, William. Germination. [Rev. of: Russell, G. A. Effect of removing 

 the pulp from camphor seed on germination and the subsequent growth of the seedling. Jour. 

 Agric. Res. 17 : 223-238. 1919 (see Bot. Absts. 3, Entry 2900) .] Dot. Gaz. 69 : 90. 1920. 



2188. GoERTZ, Otto. Untersuchungen iiber die Haustorienbildung bei Cuscuta. [Studies 

 on haustorium formation in Cuscuta.] Centralbl. Bakt. II Abt. 51: 287-313. 1920.— Ex- 

 periments are described checking and extending our knowledge of the irritability factors in- 

 volved in the production of haustoria by Cuscuta. The form worked with was C.GronomV 

 Willd., an American species found parasitizing Impatiens parviflura DC. in the botanic garden 

 at Leipzig. Haustoria can be produced on any aspect of the surface of the shoot, although 

 the inner or concave side seems to exhibit a higher predisposition in this respect; production 

 of haustoria on the convex or outer face of the stem was induced by allowing the latter to 

 twine within a glass tube. The dodder shoot must be actively growing. Mere contact with 

 a solid body, without a certain amount of pressure, is not sufficient to cause the production 

 of haustoria, as was indicated by attaching sand grains to the shoot by means of paraffine 

 oil. No haustoria are produced after flowering begins. Both twining and haustorium pro- 

 duction are inhibited on the klinostat. Contact with liquids will not induce haustorium 

 production though submerged plants may produce haustoria. A dodder plant lived 14 days 

 under water twining around and parasitizing a shoot of Myriophyllum. Exposure to radium 

 emanations inhibited all growth activity. — M. A. Raines. 



2189. Kraus, E. J. The modification of vegetative and reproductive functions under some 

 varying conditions of metabolism. Amer. Jour. Bot. 7 : 409-41G. 1920.— The author discusses 

 certain factors which tend to cause a development of vegetative organs in the plant and others 

 which stimulate reproduction. The early idea that the 2 functions are antagonistic and that 

 nitrogen stimulates only the former and potash and phosphorus the latter is now recognized 

 as incomplete. These 2 functions now seem instead to depend upon the relationship between 

 available nitrogen and the plant's supply of carbohydrates. If the former is abundant and 

 the latter scanty (as in plants with reduced leaf surface or growing in poor light) the result 

 is a plant vegetatively weak and with few or no reproductive organs. If both nitrogen and 

 carbohydrates are abundant, however, there is vigorous vegetative development but little 

 sexual reproduction. If nitrogen is limited in relation to carbohydrates, the latter will not 



