SCIENCE. 



[Vol. XIII. No. 332 



ceased, made use of filters, and it is highly probable that the poi- 

 son was preserved and increased in amount in these filters. 



It was determined to examine these filters (taken from houses 

 where there was t3'phoid) to learn whether or not they contained 

 the specific organism. As the labor of examining such an enor- 

 mous number of organisms as were found in the filters is very 

 great, only a few filters were tested. Dr. Swarts examined some, 

 and some were sent to Dr. T. Mitchell Prudden of the College of 

 Physicians and Surgeons, New York, and others to Dr. Harold E. 

 Ernst of Harvard, — all gentlemen thoroughly skilled in bacterio- 

 logical work. It must be remembered that all these filters were 

 found to be filled with decomposing organic matter, and swarming 

 with countless bacteria. The isolation of one particular species 

 among so many is a task of extreme difficulty, and negative testi- 

 mony is of little value. Even the most skilled observers abroad 

 have failed to detect this particular organism under similar condi- 

 tions, although it was known to be certainly present. In the in- 

 vestigations made for this department the organism which pro- 

 duces typhoid-fever was not found in the water itself. Bi-monthly 

 analyses of the water to determine the number of organisms were 

 made on the ist of December; but, as only a few plate-cultures 

 were made, the negative result obtained can have little value, yet, 

 as the epidemic was rapidly diminishing by the end of the first 

 week in December, it is probable that there were no typhoid or- 

 ganisms in the water itself at the time the analyses were made. 

 The typhoid organisms were, however, found in three of the filters. 

 One of these filters came from the west side of the city, and the 

 others from the east side (one from the northern, and the other 

 from the southern part). None were on the high-service supply. 



Filter No. i, a " Star " filter, was removed from the tap Dec. 8. 

 The patient was taken sick Dec. i, and the filtered water had not 

 been used for drinking-purposes since that time. There was a 

 trap, in the sink-pipe of the sink where the faucet was. There was 

 no water-closet in the house, and the stools of the patient were 

 disinfected and thrown into the vault. Filter No. 2, a " Grant " 

 filter, was removed Dec. 6. The patient was taken sick Nov. 29, 

 and died of hemorrhage Dec. 17. The plumbing of the house was 

 complicated, but perfectly trapped and in good order. Filter No. 

 3, an " Aborn " filter, was removed Dec. 6. The patient was 

 taken sick Dec. i. The plumbing was in first-class condition ; and 

 the sanitary conditions of the house, one of the finest in the city, 

 perfect. 



There is no question that the patients who used these filters 

 were suffering from true typhbid ; and there was no chance for 

 these filters, either while in position or after they were removed, to 

 become contaminated, e.xcept from the water which passed through 

 them. Besides the typhoid bacilli, several organisms characteristic 

 of fscal matter were found in the filters, indicating the source of 

 the specific contamination. In fact, one of the filters, so far as the 

 organic life was concerned, resembled, as Dr. Prudden said, a mix- 

 ture of charcoal, water, and human fseces. 



These investigations demonstrated the presence of the typhoid 

 bacillus in our public water-suppl)', and also the dangerous char- 

 acter of the domestic filters in common use, and they also prove 

 that the short epidemic of November and December last was due 

 to the pollution of the Pawtuxet RivePby the stools of typhoid-fever 

 patients. 



BOOK-REVIEWS. 



Mechanics of Engineermg. {Fluids.'] By IRVING P. CHURCH. 

 New York, Wiley. 8°. $3. 

 In the preparation of this treatise on hydraulics and pneumatics, 

 which is intended mainly for use in technical schools, the same general 

 design has been kept in view as in the preparation of the preceding 

 and companion work on solids. The author, who is assistant profes- 

 sor of civil engineering at Cornell University, has succeeded in com- 

 bining clearness with consistency in the setting- forth and illustration 

 of theoretical principles, and has provided numerous and fully lettered 

 diagrams, in which, in the greater number of cases, the notation of 

 the accompanying text can be easily apprehended. Especial at- 

 tention is invited to the proper use of systems of units in numerical 

 examples, the latter being introduced very copiously and with de- 



tailed explanations. The results of the most recent experimental 

 investigations in hydraulics have been taken advantage of in as- 

 signing values of the numerous co-efficients necessary to the more 

 thorough comprehension of the subject. Among the investiga- 

 tions thus utiUzed may be mentioned those of Fteley and Stearns 

 in 1880, and of Bazin in 18S7, on the flow of water over weirs ; 

 those of Clemens Herschel in testing his Venturi water-meter ; 

 and also some recent experiments in the transmission of natural 

 gas and compressed air. Though the action of fluid motors has 

 not been dealt with as extensively as some might have desired, 

 sufficient matter is given in treating of the mode of working steam, 

 gas, and hot-air engines, air-compressors, and pumping-engines, 

 together with numerous examples, to be of considerable advantage 

 to students not making a specialty of mechanical engineering. 



Elemenia7y Synthetic Geometry of the Point, Line, and Circle in 

 the Plane. By N. F. DUPUIS. London and New York, Mac- 

 millan. 16°. $1.10. 



This work is a result of the author's experience in teaching 

 geometry to junior classes in the University of Queen's College, 

 Kingston, Canada, for a series of years. It is not an edition of 

 " Euclid's Elements," and has, in fact, little relation to that work 

 except in subject-matter. There are a number of points in which 

 the book varies from the majority of modern treatises on geometry. 

 The point, the line, and the curve, lying in a common plane, are 

 taken as the geometric elements of plane geometry, and any one of 

 these or any combination of them is defined as a geometric plane 

 figure. Thus, the author defines a triangle as the combination of 

 three points and three lines, and he claims that this mode of con- 

 sidering geometric figures leads naturally to the idea of a figure as 

 a locus. The principle of motion and the transformation of geo- 

 metric figures recommended by Sylvester, and the principle of 

 continuity, are freely employed. 



The intention in preparing the work has been to furnish the stu- 

 dent with that kind of geometric knowledge which may enable 

 him to take up successfully the modern works on analytic geome- 

 try. 



Go to the Ant and learn Many Wonderful Things. By JOHN 

 Wentworth Sanborn. Cincinnati, Cranston & Stowe ; 

 New York, Hunt & Eaton. 12". 



iViR. Sanborn, finding that his own children were interested in 

 his experiments with ants, and that they asked him all sorts of 

 questions, sought every possible means for gaining information to 

 instruct them, and as a result of the notes put down by him from 

 time to time, of the information gathered by observation and read- 

 ing, this little book was prepared. The book tells of the social life 

 of ants, their food, the plants which they seek, the different varie- 

 ties of ants, with a chapter on foraging ants and ants as social 

 creatures. 



A Treatise on Spherical Trigonometry, and its Application to 

 Geodesy and Astronomy. By John Casey. London and 

 New York, Longmans, Green, & Co. 12°. $1.50. 

 This manual is intended as a sequel to the author's treatise on 

 plane trigonometry, and is written on the same plan. It is believed, 

 that, though moderate in size, it contains a large amount of matter, 

 much of which is original ; the author having turned especially to 

 Cr elk's Journal fiir die reine iind atigewandte Maiheinaiik, Berlin, 

 and Notmelles Annates de Matliematiques, Paris, for recent infor- 

 mation. Professor Neuberg of the University of Liege aided con- 

 siderably in its preparation. 



A Laboratory Guide in Chemical Analysis. By David O'Brine. 

 2d ed. New York, Wilejr. 8°. $2. 



This volume , is intended for the use of students who possess 

 some knowledge of chemistry, and is especially adapted to the 

 wants of the college or the medical laboratory. In the second edi- 

 tion we note that some of the chapters which were in the first edi- 

 tion have in this been greatly extended, while others are entirely 

 new. Among the items of special interest we would mention the 

 separation of substances by electrolysis, water analysis, and the 

 methods for the detection of ptomaines and alkaloid's. 



