ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 601 



fact of its motion, seems to have entered into a new phase. Dr. Pehl, 

 at St. Petersburg, has recently made a series of bacterioscoiiic 

 measurements on the waters of the capital, which are summed up in 

 the last issue of the ' Journal of the Kussian Chemical Society.' The 

 water of the Neva itself appears to be very poor in bacteria, namely 300 

 germs in a cubic centimetre. After heavy rains this number rises to 

 4500, and to 6500 during the thawing of the river. The canals of St. 

 Petersburg, on the contrary, are infested with bacteria, their 

 number reaching 110,000 in a cubic centimetre, even during good 

 weather. The same is true in regard to the conduits of water for the 

 supply of the city. While its chemical composition hardly differs 

 from that of the Neva (by which they are supplied), the number of 

 bacteria reaches 70,000, against 300 in the water taken directly from 

 the river ; and the worst water was found in the chief conduit, although 

 all details of its construction are the same as in the secondary con- 

 duits. Dr. Pehl explains this anomaly by the rapidity of the motion 

 of water, and he has made direct experiments in order to ascertain 

 that. In fact, when water was brought into rapid motion for an 

 hour, by means of a centrifugal machine, the number of developing 

 germs was reduced by 90 per cent. Further experiments will show 

 if this destruction of germs is due to the motion of the mass of water, 

 or to molecular motion. The germs, among which Dr. Pehl distin- 

 guishes eight species, are not killed by immersion in snow. As 

 the snow begins to fall it brings down a great number of germs, 

 which number rapidly diminishes (from 312 to 52 after a three 

 hours' fall of snow, on January 21st, 1884), while their number on the 

 surface of the snow increases, perhaps in consequence of the evapo- 

 ration of snow or of the condensation of vapour on its surface. 



Bacteria from Coloured Fishes' Eggs.*— Dr. Peter has investi- 

 gated the causes of various colouring of the eggs of Goregonus 

 Wartmanni, red, blue, and yellowish-brown, and finds it to be due to 

 the presence of bacteria, which frequently entirely filled up the 

 interior of the egg. The colour itself was due to drops of oil ; 

 the bacteria themselves were always colourless, and of the following 

 kinds: — (1) slender smooth motile rods with short segments; (2) 

 thicker motile rods; (3) very thick, straight, smooth, motionless rods 

 (rare) ; (4) very slender, straight, smooth, motionless filaments ; (5) 

 microwKci. There was also not unfrequently a Saprolegnia present. 

 These bacteria were cultivated in a large number of different nutrient 

 fluids, when all transitions from them to a spirillum form appeared ; 

 as also a transition from the leptothrix form No. 4, to a spirillum. A 

 transformation appears to take place of ordinary bacteria into those 

 which are the cause of the colouring of the eggs. 



Bacteria connected genetically with Algae-f— H. Zukal has 

 contiuued his investigations | as to the genetic connection between 



• Ber. Bot. Verein Miinchen, Sept. 19, 1883. See Dot. Centrall»l , xviii. 

 (1884) p. 92. 



t Oesterr. Bot. ZeitBclir, xxxiv. (1884) pp. 7-12, 41)-.'»1. 

 t See thin Journal, iii. (IKKI^j p. 400. 

 Ser. 2.— Vol. IV. 2 S 



