ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 755 



spores. Superficial colonies appear as round pink transparent drops 

 with a faint green reflection ; the deeper colonies are smaller and more 

 compact, round or irregular ; individual organisms present many poly- 

 morphic forms. Vitality is retained in cultures for at least two years. 

 Cultures may be obtained on all nutrient media ; the optimum tempera- 

 ture is 37° C. ; growth appears on gelatin at room temperature after 

 6 weeks ; there is no gas formation in media containing the various 

 sugars. 



By injecting pure culture into the veins, vagina, or uterus of an 

 enceinte cow, Bang obtained abortion. The author found that inocula- 

 tion of female guinea-pigs and rabbits produced abortion in almost 

 every case. 



Five New Species of Iron-bacteria.* — D. Ellis gives preliminary 

 notes of five new species of iron-bacteria. 



1. Spiro soma f err ugineum consists of regular wavy threads, with wave- 

 lengths two to three times the amplitude, and varying in size from a 

 few fL to 100 /u. or more. Reproduction is-effected by formation of conidia, 

 and rarely by a splitting process. The organism is present in all Scottish 

 iron-waters, excepting those of the extreme northern counties ; it has not 

 been found in English iron-waters. 



2. jSTodofoUum ferrugineum consists of a flat band constricted at 

 regular intervals, varying greatly in the sizes and in the number of the 

 constrictions : reproduction occurs by conidia formation, which swells out 

 the band to double its normal thickness. This organism occurs in the 

 central and western parts of Scotland, but not in the north and south. 



3. Leptothrix Meyer i resembles L. ochracea, but differs from it in the 

 absence of shapely contoured walls, and in the appearance of the iron 

 deposit, which is transparent at first and becomes opaque later. The 

 threads vary in length from 40-70 /*, and in breadth from 2-3 fx. 

 The transparent nature of the iron deposit is due to mucilage formed by 

 the degeneration of the thread-walls ; the iron slowly penetrates, and 

 colouring the mucilage renders it visible. The method of reproduction 

 has not been studied. 



4. Spirophyllum tenue consists of a spirally twisted flat band, 1 /j. in 

 width and from 200-300 /x long, as many as 200 spirals occurring in one 

 individual. It has a loose solenoid structure, and only a slight iron 

 deposit, which is detected by ammonium sulphide and with potassium 

 ferrocyanide. The complete life-history has not been established. 



5. Spirosoma solenoide resembles the preceding. But the spirals 

 are very close together, and made up of a thread, not a band ; the 

 average individual measures about 70 //., the thread is 0'5/x in diameter, 

 and the distance between two turns is less than 1 //. The complete 

 life-history has not been established. 



Lactic Acid Fermentation in Milk.f — M. W. Beijerink finds that 

 in the various forms of lactic acid fermentation there is no formation of 

 gas, or only of carbonic acid, and sometimes there is a vigorous slime 



* Proc. Rov. Soc. Edinburgh, xxviii. (1907-8) p. 338. 

 t Konink. Akad. Wetensch., x. (1907) p. 17. 



