778 



SGIENGE. 



[N. S. Vol,. IV. No. 100. 



entiate in sewage waters ; but it is probably 

 killed in those waters, by exposure to sun- 

 light, before this power is entirely lost. 

 The members of the colon bacillus group 

 which have been obtained by the writer 

 from contaminated waters have rarely pos- 

 sessed the fermenting power which is found 

 in cultures obtained from the normal intes- 

 tines 'of man ; they may be in a ' transi- 

 tional' state. 



The greater loss of fermenting power with 

 saccharose than with other sugars, may be 

 attributed to the nature of the sugar, which 

 is not directly fermentable, but must first 

 be inverted by a ferment, dextrose and 

 levulose being formed, in which the pro- 

 cess of fermentation is easily carried on. 

 The duration of the fermenting process of 

 the colon bacillus with saccharose is much 

 longer than with other sugars. 



The diminution in fermenting power 

 noted in cultures obtained from organs un- , 

 dergoing inflammation will be further 

 studied in connection with the influence of 

 proteid materials on the colon bacillus. 



My thanks are due to Dr. J. S. Billings 

 and Dr. A. C. Abbott for direction in this 

 work, and assistance in obtaining cultures ; 

 and also to Dr. Henry W. Cattell, who has 

 furnished me with much valuable material. 

 Adelaide Ward Peckham. 



Laboeatoey of Hygiene, 

 Univbesity op Pennsylvania. 



1. Achard and Eenault. Sur les different types de 

 bacille urinaires appartenant au groupe du bacterium 

 coli. Compt. rend, soc de biol., 1892, 9836. 



2. Tavel, Caracteres diff^rentiels du bacteria. 

 Semaine Medicale, 1892, no. 8. 



3. Stoeklin. H. de. Researches sur la mobilite et 

 les cils de quelques representants du groupe des coli 

 bacillus. Annales Suisse des sc. med., 1, 1814, 471. 



4. Gilbert. On Colibacillosis. Medical "Week, 

 Par. Gei., 1895, 111., Gc. 



5. Fremlin. Vergleiche Studien an Bacteriacoli 

 commune verscMedener Provienz. Arcbiv fiir Hy- 

 giene, Bd. XIX., p. 295. 



6. Eefik. Sur les divers types le coli-bacille des 

 Eaux. Annales de I'Institut Pasteur, April 25, 1896. 



7. Smith, T. Notes on bacillus coli communis and 

 related forms, etc. The American Journal of Medical 

 Sciences, Vol. CX., No. 3, No. 281. 



8. Pere, A. Contribution a la biologic du bacte- 

 rium coli commune et du bacille typhique. Annales 

 de I'Institut Pasteur Tome VI. , 512 ; Sur la formation 

 des acides lactiques isonieriques par Faction des mi- 

 crobes s\ir les substances hydrocarbonn^es. Annales 

 de I'Institut Pasteur Tome VII., 737. 



9. Ohlmacher : Medical News, July, 1895. 



10. Villinger. Ueber die Veranderung des bac- 

 terium coli commune durch aussere Einfliisse. Archiv 

 fiir Hygiene Bd. 21, Heft. 2. 



12. Wathelet, A. Recherches bacteriologiques sur 

 les dejections dans la fi^vre typhoide. Annales de 

 I'Institut Pasteur, April, 1895. 



SUPERHEATED STEAM IN STEAM ENGINES. 



The writer has been, for many years, 

 much interested in the now century-old 

 problem of the application of superheated 

 steam to use in the steam-engine with a 

 view to the extinction of those internal 

 thermal wastes which have, from the days 

 of Watt, been recognized more or less 

 clearly as the most formidable obstacles in 

 the way of improvement of the eflSciency of 

 the steam-engine, as in fact, of all known 

 heat-motors. The material which has been 

 meantime collecting was recently collated 

 and abstracted, and finally published in a 

 paper read before the American Society of 

 Mechanical Engineers at its St. Louis meet- 

 ing of 1896.=i^ The subject has more of sci- 

 entific than practical interest at the mo- 

 ment ; but it is not impossible that the re- 

 suscitation of this once accepted and now 

 comparatively little-used process may yet 

 prove to be the means, and the only prac- 

 ticable means, of continuing indefinitely the 

 improvement of the steam-engine begun by 

 Watt a century ago. The alternative seems, 

 at the present time, to be the discovery of 

 some commercially practicable method of 



* Superheated steam ; facts, data and principles re- 

 lating to the problem. Trans. A. S. M. E., 1896, 

 Vol. XVII. 



