18S2.J 



MICEOSCOPICAL JOUENAL. 



237 



measurements were published at all 

 under such circumstances ? Perhaps 

 some one who knows will tell us whe- 

 ther that particular micrometer is the 

 one that has been frequently used 

 to demonstrate the imperfections of 

 Prof. Rogers' rulings. If so, we might 

 "a plain, unvarnished tale" unfold 

 about that same micrometer. Mr. 

 Henry Mills has a valuable article on 

 the " Fresh-water Sponge." There 

 are 178 names on the list of members. 



The Society deserves to be con- 

 gratulated for the thoroughness and 

 promptness with which the Commit- 

 tee on Publication, consisting of Prof. 

 Kellicott, Prof. McCalla and Mr. Fell, 

 have done their work. 



Copies of the Proceedings can be 

 obtained, we presume, of Mr. Geo. E. 

 Fell, at Buffallo. 



Sewer Gas. — Dr. Frank Hamil- 

 ton has an article on sewer gas in 

 Popular Science Monthly^ of Novem- 

 ber, from which the following is 

 taken : — 



" This term has been employed a 

 long time by chemists, sanitarians, 

 plumbers, and others, to indicate the 

 ordinary emanations from sewers ; 

 but recently certain gentlemen have 

 taken exceptions to the term, deny- 

 ing that there is any such thing as 

 sewer gas ' having a peculiar and de- 

 finite composition.' This is undoubt- 

 edly true, and it is probable that no 

 intelligent man or educated physi- 

 cian ever thought otherwise. 



" What has been called ' sewer 

 gas ' is composed of air, vapor, and 

 gases, in constantly varying propor- 

 tions, together with living germs — 

 vegetable and animal — and minute 

 particles of putrescent matter. In 

 short, it is composed of whatever is 

 sufficiently volatile or buoyant to 

 float in the atmosphere, and in con- 

 sequence of which buoyancy it is per- 

 mitted to escape through the various 

 sewer outlets. The term is, in this 

 sense, well understood ; and it is, 

 moreover, just as correct as would be 



the terms sewer vapor, or sewer air, 

 which some have chosen to substitute 

 for it". 



" It is proper here to add that the 

 offensiveness of odors is no test of 

 their insalubrity, but that the most 

 fatal germs are often conveyed in an 

 atmosphere which is odorless. The 

 absence of unpleasant odors, there- 

 fore, furnishes no proof that the air 

 does not contain sewer emanations." 



A New Method of Attaching 

 Objectives. — Mr. James L. Pease, of 

 Chicopee, Mass., has constructed a 

 nose-piece of new and ingenious de- 

 sign, intended to facilitate the attach- 

 ing and detaching of objectives to 

 and from the body of the microscope. 

 Its operation resembles that of the 

 self-centeringchucks used by mechan- 

 ics ; the objective is held firmly as in 

 a vise, and its centering is perfect. 

 Changing objectives is accomplished 

 with great rapidity and ease, without 

 the troublesome screwing up and un- 

 screwing. 



The nose-piece can be applied to 

 any stand having the society screw, 

 no alteration of either stand or ob- 

 jectives being required. It is neat in 

 appearance and not at all cumber- 

 some, and adds but little to the length 

 of the tube. It will be more fully 

 described after we have had an op- 

 portunity to test it in practice. 

 o 



The Microbes of Disease. — Dr. 

 D. E. Salmon spoke for a few moments 

 at a recent meeting of the New York 

 Microscopical Society, and incidental- 

 ly made some allusions to some ob- 

 servations tending to cast doubt upon 

 the supposed bacillus of tuberculosis. 

 In his own experiments he found a 

 diplococcus form in a rabbit which 

 was affected with tubercular disease, 

 which seemed to be the same as a di- 

 plococcus which had previously been 

 described as the cause of tuberculosis. 

 Koch had described a totally differ- 

 ent form — a true bacillus. Later ob- 

 servers have failed to discover either 

 form. 



