August 8, 1913] 



SCIENCE 



195 



and only then in the absence of wind. They 

 enter dwellings if not too brightly lighted, but 

 are not natural frequenters of human habita- 

 tions. They breed in caves, rock interstices, 

 stone embankments, walls, even in excavated 

 rock and earth materials. The verruga can- 

 yons contain ideal conditions for such breed- 

 ing. They hide by day in similar places or in 

 shelter of rank vegetation. Deep canyons, 

 free from wind and dimly lighted, are espe- 

 cially adapted to them. Thick vegetation pro- 

 tects them from what wind there is by day or 

 night. This explains the very peculiar re- 

 stricted distribution of verruga both local and 

 altitudinal. The flies suck the blood of almost 

 any warm-blooded animal, and even that of 

 lizards in at least one known case. Thus they 

 are quite independent of man, and this accords 

 with the verruga reservoir being located in 

 the native fauna. The habits of Phlehotomus 

 correspond throughout so minutely with the 

 conditions of verruga and the verruga zones 

 that the writer wishes to announce his entire 

 confidence in the belief that the transmission 

 experiments, now about to be initiated with 

 these gnats on laboratory animals, will demon- 

 strate their agency in the transmission of the 

 disease. 



Charles H. T. Townsend 

 Chosica, 



June 29, 1913 



SCIENTIFIC BOOKS 

 Examination of Waters and Water Supplies. 



By John C. Thresh. Second edition. 



Philadelphia, P. Blakiston's Son & Co. 



1913. 644 pages ; 36 plates ; 16 illustrations 



in the text. Price $5. 



This is a new edition of a. book that is well 

 known to American waterworks engineers. 

 The author is one of the foremost water an- 

 alysts in England and the book shows evi- 

 dences that it is written by one who speaks 

 with authority. It is needless to describe the 

 book in detail. 



Part I. relates to the examination of the 

 sources from which water is derived. Part II. 

 treats of the various methods of examining 

 water and the interpretation of the results of 



such examinations. Part III. describes in 

 more detail the analytical processes and meth- 

 ods of examination. 



Most American readers will be particularly 

 interested in the first three chapters that re- 

 late chiefly to ground water. The author de- 

 scribes numerous personal experiences in the 

 detection of underground pollution, and an 

 excellent description is given of the use of 

 fluorescein, and other substances which may 

 be detected either by sight or by smell, in 

 tracing the course of water through the 

 ground. From his experience he states that 

 water which enters a dug well at a depth of 

 six to twelve feet, depending upon the porosity 

 of the soil, is usually efficiently filtered and 

 purified. Water entering at a less depth is 

 nearly always liable to be imperfectly purified 

 and unsatisfactory in quality. The nearer the 

 ground surface at which water can enter the 

 greater the danger of pollution. 



One statement of the author will strike 

 most readers with surprise, namely, " Every 

 known fact with reference to typhoid fever 

 epidemics indicates that the typhoid bacillus 

 alone is not the cause of disease, and it has 

 long been suspected that some other organism 

 either by itself or in conjunction with the 

 typhoid bacillus was the cause." He then 

 quotes from an article in the Lancet and de- 

 scribes a new anaerobic bacillus which has 

 been found only in the feces of typhoid fever 

 patients and which is agglutinated by their 

 serum. It is a spore-bearing organism and is 

 said to be capable of retaining its vitality for 

 a very long period. 



An interesting example of the grovrth of 

 organisms in water mains is mentioned. A 

 thirty-six-inch main at Hampton-on-Thames 

 was recently taken up and found to contain 

 fresh-water mollusks to such an extent that 

 its bore was reduced to nine inches. It was 

 estimated that ninety tons of mussels were 

 removed from a quarter of a mile of this main. 



Beference is made to the ill effect of the 

 continued use of soft waters on the human 

 system, and a method of artificially hardening 

 water by the addition of calcium chloride and 

 sodium bicarbonate is described. 



