ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 523 



Roger ; another is designated Streptothrix/usea ; the third is identified 

 as the 8. Candida gedanensis II Petrnschsky. The author expresses the 

 opinion that Streptotricheae are an important feature of tuberculous 

 sputum. 



Cytology of the Bacteria.* — C. C. Dobell in a contribution to the 

 cytology of the bacteria, draws the following conclusions : All bacteria 

 which have been adequately investigated are — like other Protista — 

 nucleate cells. The form of the nucleus is variable not only in different 

 bacteria but also at different periods in the life-cycle of the same species. 

 The nucleus may be in the form of a discrete system of granules 

 (chromidia) ; in the form of a filament of variable configuration ; in the 

 form of one or more relatively large aggregated masses of nuclear sub- 

 stance ; in the form of a system of irregularly branched or bent short 

 strauds, rods, or networks ; and probably also in the vesicular form 

 characteristic of the nuclei of many animals, plants, and protists. There 

 is no evidence that enucleate bacteria exist. The bacteria are in no way 

 a group of simple organisms, but rather a group displaying a high degree 

 of morphological differentiation coupled in many cases with a life-cycle 

 of considerable complexity. 



Bacterium Briosii.f — G- L. Pavarino gives a preliminary account of 

 a new species of bacterium which attacks the tomato. B. Briosii differs 

 in many respects from B. solanacearum Smith, which also causes tomato 

 rot. The rodlets are short and stumpy. The optimum temperature is 

 15-16° C. A yellow pigment is formed. Pure cultures reproduce the 

 disease in healthy plants. 



Action of Wax-solvents and the Presence of Thermolabile Bacterio- 

 toxins on Soil.J — R- Greig-Smith thus summarizes his experiences : 

 "Water extracts from soil a substance which is filtrable through porcelain 

 and which is toxic to bacteria. The toxicity is made evident by the 

 retardation of growth or by the destruction of the bacteria. The toxin 

 is destroyed by heat, by sunlight, and by storage. It slowly disappears 

 from air-dried soil and rapidly decays in aqueous solution. It is not 

 destroyed by salts, such as sodium chloride, potassium or magnesium 

 sulphate. Soils vary in the amount of toxin they contain ; good soils 

 contain less, poor soils more. The particles of soil are covered or 

 " waterproofed " with soil-wax or " agricere," which consists of a mixture 

 of saponifiable and unsaponifiable bodies. The wax-solvents (volatile 

 disinfectants) alter the distribution of the agricere by carrying it to the 

 surface of the soil and causing it to be segregated on the points of the 

 soil particles. "With the removal of the " waterproofing " the soil- 

 nutrients are more easily dissolved by soil-water and attacked by bacteria. 



Tuberculosis. — "W. Bulloch, in the Horace Dobell Lecture, delivered 

 before the Royal College of Physicians in November 1910, draws the 

 following conclusions : Pulmonary tuberculosis is produced almost, if 

 not exclusively, by bacilli of the tijpus humanus ; it is essentially an 



* Quart. Journ. Micr. Sci , lvi. (1911) pp. 395-506 (4 pis.). 



f Atti R. Accad. Lincei, xx. (1911) pp. 355-8. 



j Proc. Linn. Soc. N.S.W., xxxv. (1910) pp. 808-22. 



