Report on the Bacteriology of Water. 



189 



§ I. Schizomycetes actually Detected in Natural Waters. 



It has long been known that natural waters, of rivers, springs, 

 ditches, wells, lakes, &c, contain bacteria, often in enormous quanti- 

 ties ; and prolonged experience has shown that no kind of ordinary 

 water, whether running or standing, is entirely devoid of these 

 organisms ;f though the rule is that the waters of rivers usually con- 

 tain many more organisms than those of lakes or large reservoirs. 

 Mountain streams are generally less rich in bacterial life, while 

 stagnant or slowly moving waters usually contain many and often 

 peculiar species. 



Some of the best studied and longest known aquatic species are 

 the following: — Cladothrix dichotoma (Cohn), Crenothrix Kuhniana 

 (Rabenh.), Sphcerotilus natans (Kiitz.), Beggiatoa alba (Vauch.), 

 Spirillum plicatile (Ehrenb.), Bacillus erythrosporus (Cohn), Bacterium 

 janthinum (Zopf), Bacterium merism&pedioides (Zopf). There are, 

 however, many other forms known to occur in water : e.g., Sarcina 

 Beitenbachii (Caspary), S. hyalina (Kiitz.), Spirillum serpens* (Miiller), 

 S. teaue* (Ehrenb.), S. undula* (Miiller), S. volutans* (Ehrenb.), 

 Manas vinusa* (Ehrenb.), M. OJcenii* (Ehrenb.), M. gracilis (Warm.), 

 Bhabdomonas rosea* (Cohn), Myconostoc gregarium (Cohn), Spiro- 

 monas Gohnii (Warm.), Micrococcus cr&pusculum* (Ehrenb.), M. griseus 

 (Warm.), Clathrocystis roseopersicina (Kiitz.), Bacterium Termo* 

 (Dujard.), B. lineola (Miiller), Bacillus tremulus (Koch), B. Ulna* 

 (Cohn), B. virens (Van Tiegh.), and many others. J 



With regard to this last list, two remarks are necessary. In the 

 first place, most of the species or forms named are characteristic of 

 waters containing much vegetable or animal matter in a state of 

 decay, whence they are commoner in marshes, ditches, ponds, &c, 

 than in running streams, rivers, and wells ; and, in the second, some 

 of the so-called species are certainly not good ones, but what are 

 usually termed " form-species," requiring further examination, and 

 especially by means of continuous cultures. The latter applies par- 

 ticularly to the forms marked * in the above list ; we do not accept all 

 the others as satisfactory species, but it is difficult to say anything 

 definite about them. One form (Clathrocystis roseo-persicina) has been 

 shown by Lankester§ and Zopf || to be very polymorphic, and it 



+ ' Cohn, ' Beitrage zur Biologie der Pflanzen,' from 1870 ; as well as in numerous 

 reports concerning drainage from sugar factories, Magdeburg, 1886 ; Hirt, ' Zeitschr. 

 f. Biologie,' 1879, vol. 15, p. 91 ; Evferth, ' Die Mikroskopischen Siisswasserbewohner,' 

 1877; Kirchner and Blochinann, 'Die Mikroskopische Pflanzen- und Thierwelt des 

 Susswassers,' 1886 ; Hulwa, ' Biedermann's Centralbl. f . Agrikulturchemie,' 13, Pt I. 



X See Appendix A for literature. 



§ Who named it Bacterium rubescens. 



|| Who terms it Beggiatoa roseo-persicina. 



