ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 483 



nitrates are reduced to nitrites ; milk becomes strongly acid, and 

 " appears to thicken." 



Researches on the Bacteria found in the Intestine of the Larva 

 of Mosca Olearia.* — L. Petri describes the characters of an organism 

 isolated from the proventrieular caxsi of this larva. Cultures were made 

 from dilutions of the contents of the caeci, and grown aerobically on 

 ordinary media ; all cultures grown under anaerobic conditions remained 

 sterile. The colonies obtained on peptonised agar at 30° C. have a 

 circular contour, increasing from 1 mm. to a very great diameter ; they 

 are of a yellow ochre colour ; they have a central conglomerate portion, 

 consisting of capsulated elements and alternating rings of freely motile 

 bacteria and capsulated elements. Growth on gelatin is very slow, and 

 the medium is liquefied. The yellow colonies are composed of very 

 short cocco-bacilli, which attain a greater length on media containing 

 large quantities of fatty matter, and in the intestine of the larva. The 

 motile forms show five long peritrichous flagella ; the yellow pigment is 

 not soluble. From its possessing a voluminous capsule enclosing often 

 great numbers of bacilli and resembling a true Zoof/kea, he assigns this 

 organism to the group of capsulated bacteria described by Babes as the 

 genus Ascobacterium. The bacillus is common in moist soils, and is con- 

 stantly found in the soil of the olive, and has been isolated from the 

 cortex of the same olive plant, and at the end of the larval period, from 

 the channels excavated by the larva ; the larvae, 1^ mm. long, have 

 their four caeci completely full of these bacilli, and it is noteworthy that 

 this accumulation of bacilli constitutes a tenth of the entire volume of 

 -the larva. 



The resistance of the bacillus to acids is very weak ; a 0*01 p.c. solu- 

 tion of tartaric acid is sufficient to arrest or impede its development ; its 

 resistance to fatty acids is much greater. It produces oxalic acid by its 

 oxidising action on hydrocarbons ; nitrates are not reduced ; it does not 

 form indol ; it secretes a proteolytic enzyme that dissolves gelatin and 

 peptonises milk ; during its capsulated state it produces a substance of 

 mucilaginous consistence that has the properties of pectin. From 

 experiments made to ascertain the nature of its action on olive oil, it is 

 suggested that the lipolytic action of the bacillus is effected by an ecto- 

 enzyme poured out into the fluid culture, since, if this latter is filtered 

 and placed in contact with a monobutterine, it shows a very energetic 

 lipolytic action. The abundant secretion by this organism of a lipase, 

 and its localisation in the intestine of the larva, whose nourishment is 

 composed chiefly of fatty substance, makes it probable that between the 

 larva and the bacterium there exists a symbiotic relationship. 



Micro-organism showing Rosette Formation.! - - Mabel Jones 

 describes a spirillum-like organism isolated from water and sewage. 

 Twenty-four hours' old cultures on agar consist of short, plump commas 

 1'5/i — S/i long, and 0'5fi — 0'7 fi broad, with pointed ends, and 

 arranged as spiral filaments, sigmaa and rosettes, which last are in no 

 way an agglutination phenomenon ; the single polar flagellum of each 



* Atti Reale Accad. Lincei, xiv. (1905) p. 399. 

 t Centralbl. Bakt., 2 to Abt., xiv. (1905) p. 459. 



2 K 2 



