POPULAR MISCELLANY. 



4 2 3 



Pathology. By J. N. De Hart, M.D. From the 

 " Chicago Medical Journal and Examiner. Pp. 

 12. 



On a Mode of measuring the Velocity of 

 Sound in Wood. By M. C. Ihlseng, Ph.D. From 

 the "American Journal of Science and Arts. 

 Pp.8. 



A New Form of Compass-Clinometer. By 

 I C. Russell. From " Annals of the New York 

 Academy of Sciences." Pp. 2. 



In the Matter of Certain Badly Treated Mol- 

 lusks. By R. E. C. Stearns. Pp. 10. 



POPULAR MISCELLANY. 



Well-Water and Typhoid Fever. In the 



summer of 1878 some forty persons in 

 Rochester, whose supply of drinking-water 

 was derived from a certain well, were taken 

 sick with typhoid fever and other zymotic 

 diseases. The health officer had the well 

 closed, so that the people had to get water 

 from other sources. Their recovery was 

 rapid from that moment. A request was 

 then addressed to all the physicians in the 

 city to report the names and residences of 

 all persons sick with typhoid fever. About 

 fifty cases having been reported, health in- 

 spectors were sent to the various localities, 

 who inquired into their sanitary conditions, 

 the distance of cesspools, sewers, and privy- 

 vaults from the wells ; also whether the pa- 

 tients drank well-water either at their homes 

 or at their places of business. Samples of 

 water were taken from the wells, and sub- 

 mitted for analysis to Dr. Lattimore, Pro- 

 fessor of Chemistry in the University of 

 Rochester. The result of the inquiries was 

 to show that, of the whole number of cases 

 of typhoid reported, all but two had followed 

 from the use of well-water ; the exceptional 

 cases arose from ill-ventilated apartments 

 in close proximity to foul water-closets. It 

 was also ascertained that a very large num- 

 ber of the wells in the city were situated 

 within an average distance of less than thir- 

 ty feet from cesspools and privy-vaults, 

 while a great many were distant from them 

 not over ten feet ! In Professor Lattimore's 

 report occurs one passage which must be 

 quoted in extenso, namely, the one in which 

 he remarks on the significance of the pres- 

 ence of common salt in well-water : " I 

 would direct your special attention to the 

 second column " [of his table showing the 

 amount of solid matters in the water], 



" which shows the number of grains of 

 common salt per gallon of water. No sin- 

 gle indication is of so great sanitary impor- 

 tance in judging of the purity or impurity, 

 and consequently of the safety or danger, 

 of any water. How a substance, which is 

 in itself not only harmless, but by most 

 persons considered indispensable as an ar- 

 ticle of diet, becomes to the sanitarian a 

 signal of danger in well-water, will be easily 

 rendered apparent. No mineral substance 

 is perhaps so universally diffused as com- 

 mon salt. It exists in the air, hence in all 

 rain-water ; in all soils, hence in all well- or 

 spring-water, though often in quantities too 

 minute to be weighed upon the chemist's 

 balance, as is the case in the Hemlock Lake 

 water of this city. Salt being remarkably 

 soluble, it is constantly being washed out of 

 the soil into the streams, and ultimately 

 carried down to its great reservoir, the 

 ocean. We may, therefore, expect to find 

 salt present in all ordinary well-water. 

 What might fairly be considered as the 

 average proportion for uncontaminated well- 

 water in Rochester can be only estimated, 

 but it certainly can not be large. Rivers 

 may derive large quantities of salt from the 

 drainage of manufacturing establishments 

 upon their banks, but wells are not usually 

 thus affected. Therefore, whenever, in well- 

 water, it rises above a very few grains per 

 gallon, it becomes certain that it comes from 

 some other source than the soil. What is 

 that source? A moment's reflection will 

 convince any one that nearly all the salt 

 used for domestic purposes escapes by the 

 way of two channels the water-closet and 

 the house-drain. Therefore, we should ex- 

 pect, what is always found on examination 

 to be true, that whatever sewage may or 

 may not contain, it always contains salt." 



Improved Diaphragm for the Phono- 

 graph. Messrs. Preece and Stroh exhibited 

 at a recent meeting of the London Royal 

 Society a new form of diaphragm, which in- 

 tensifies the loudness and removes some of 

 the imperfections of the present disk of the 

 phonograph. They had sought for a dia- 

 phragm which should give all the finest 

 shades of sonorous vibrations, and, after 

 trying many substances, a stretched mem- 

 brane of thin India-rubber, rendered rigid 



