ZOOLOGY AND BOTANY, MTCROSCOPYj ETC. 545 



agree with what occurs in heteromerous crustaceous lichens as 

 Grapliidea, but the perithecia indicate its angiocarpous alliance, 

 bringing the form nearer such families as Pertusaria and Verrucaria, 

 to the latter of which it may ultimately be referred. 



Algae. 



Vegetation of Street Gutters.* — The discovery that, among the 

 causes of epidemic diseases, microscopical organisms play an im- 

 portant part, is a great advance in the cause of science, which 

 is capable of much further development. Dr. Hugo Winnacker 

 communicates a number of observations which he made in the town 

 of Gottingen, laying stress on the fact that scarcely any other water 

 is subjected to greater change than that in running street gutters. 

 Every hour produces deviations in the water-level, and from the dried 

 edges every current of wind may carry germs which only need damp 

 to regain active life in the habitations and breathing-places of men. 



The small vegetable organisms which are now found in the 

 running gutters of Grottingen, vary much according to the season of 

 the year and the particular locality, and, as often happens in nature, 

 the rapid multiplication of one checking that of another, the one 

 supplants the other. The author notes down, according to months 

 and particular streets, the genera, and species which he found in the 

 gutters of Gottingen from October 1877 to August 1878. There 

 occurred partly green or black filamentous algae (amongst which were 

 Oscillaria, Vaucheria, Zygnema, and Cladophora), partly diatoms, and 

 partly fungi, among which, besides Leptothrix and Fiisisporium (of 

 which a new species is described), are notably micrococcus, bacillus, 

 spirillum, and bacterium ; the most suspicious found in the greatest 

 quantity. 



With regular plentiful rinsing through clean water, the algfe were 

 predominant, and next to them the fungi. The vegetation is at its 

 greatest activity from May to July. Fungi and algae struggle against 

 one another for existence, each prevailing as the circumstances favour 

 the one or the other. The drought of summer and the cold of winter 

 chiefly destroy the algae and also a few fungi, but not micrococcus, 

 bacillus, and bacterium, so that these thereby have the advantage. 



AlgaB are not injurious to men ; but are, on the contrary, useful 

 as regulators of vegetation. Green gutters are in no way detrimental. 

 Among the fungi, moulds are harmless to the human organism. The 

 only ones which are harmful as promoters of fermentation and 

 spreaders of infection are the Schizomycetes, to which belong micro- 

 coccus, bacterium, bacillus, &c. The following, in the words of the 

 author, are the principal rules to observe for the preservation of 

 public health : — 



1, By constant and abundant flushing with clean water the street 



* Winnacker, H., ' Ueber die niedrigsten, iu Einnsteiu?n beobnchteten 



pflanzlichen Oiganismen,' 4to, Elberfeld, 1883, 19 pp. and figs. Cf. Natur- 

 forscher, xvi. (1883) pp. 153-4. 



Ser. 2.— YoL. III. 2 N 



