April 22, 1887.] 



SCIUJVG^. 



397 



SANITARY EXAMINATIONS OF WATER, 

 AIR, AND FOOD. 



The first edition of this book, which appeared 

 in 1878, supplied a want, which had long been 

 felt by health-officers, for a book which would 

 help them to solve the problems which presented 

 themselves for solution almost daily in their ef- 

 forts to provide, for those committed to their care, 

 pure water, air, and food. Dr. Fox's brochure on 

 water-analysis was recognized as a work of great 

 value, and two editions of it had been exhausted. 

 When a third edition was called for, its scope was 

 extended by adding sections on the examination 

 of air and food. In the section devoted to the 

 sanitary examination of drinking-water, we find 

 all the well-known tests for the determination of 

 organic matter, and, in addition, the biological 

 method of Koch, which, in Germany at least, 

 is regarded as being as important as the chemical 

 analysis. Chemistry gives no indication of the 

 presence or the number of micro-organisms ; and 

 there is no doubt that water has been declared 

 suitable for drinking-purposes, as a result of 

 chemical analysis, when, had the biological meth- 

 od been known and employed, a far different 

 opinion as to its potability would have been given. 



The determination of the nature and life-his- 

 tory of the microbes found in water is too difficult 

 for the health-officer, unless he be at the same 

 time a bacteriologist, and so situated as to be able 

 to investigate them in a properly equipped labora- 

 tory ; but the ability to ascertain whether their 

 number in a given water is beyond the normal 

 amount is certainly within his reach. The methods 

 to be employed in such an examination are fully 

 described, and the apparatus abundantly illus- 

 trated, in the work before us. In a table given by 

 the author, showing of what this method is capa- 

 ble, it is observed that the number of micro- 

 organisms in the different metropolitan waters 

 varies markedly at different seasons, and in the 

 waters as compared with each other. In the 

 water of the Thames at Chelsea, in January, there 

 were 8 in one cubic centimetre ; in February, 33 ; 

 in June, 81 ; in September, 13 ; and in November, 

 3. In the water of the River Lea there were 25 

 in January, 121 in May, and 817 in December. 

 The water of the Kent company leaves the well 

 almost wholly destitute of organic life, and the 

 few organisms which it contains are imported into 

 it en route to its supply. 



In the chapter descriptive of the microscopic 

 examination of water there is much that is valu- 

 able. By the aid of the microscope, an approxi- 

 mate estimate may be made of the number of 



Sanitary examinations of water, air, and food. By 

 Cornelius B. Fox. 2d ed. Philadelphia, Blakiston. 12°. 



micro-organisms and the diagnosis of the kind, — 

 whether bacteria, bacilli, micrococci, vibrios, spi- 

 rilla, etc. The kind of animal and vegetable life 

 seen in water gives a certain clew to the descrip- 

 tion of the water under examination. The In- 

 f usoriae, Conf ervae, and Vorticellae are the inhab- 

 itants of the least pure of spring- waters ; then 

 come the diatoms and desmids ; Entomostraca, or 

 water-fleas, are seen in spring-ponds, lochs, and 

 impounded waters ; euplota and fungoid growths 

 abound in ditch and pond waters, and in well- 

 water polluted with filth ; whilst bacteria, para- 

 mecia, and spirilla are prominent in sewage-pol- 

 luted water. Dr. Frankland regards the presence 

 of any thing like a moving organism in a water as 

 a danger-signal, for the reason that, if the poisons 

 of such diseases as cholera and typhoid-fever at- 

 tach themselves to particles of organic matter, 

 and can operate in inconceivably minute quanti- 

 ties, as is generally believed, there is a possibility 

 of the disease-ferment or germ of such maladies 

 accompanying elementary forms of life. Two 

 plates are given of microscopic objects found in 

 drinking-water. 



In the section which takes up the sanitary ex- 

 amination of air, the author describes the various 

 impurities found in air which render it unfit for 

 respiration, including'sewage emanations, poison- 

 ous gases and injurious vapors, emanations from 

 ground having damp and filthy subsoil, and from 

 churchyards, and the deleterious effects on health 

 of impure air in our houses. The methods for 

 the detection and estimation of the amount of the 

 most important impurities found in the air are 

 fully dealt with, including both the microscopical 

 and biological methods. Chapters are also de- 

 voted to ozone, temperature, solar radiation, bar- 

 ometric pressure of the air, direction of the wind, 

 etc., and their relations to health. 



One of the most interesting chapters in the book 

 is that which treats of the meteorological condi- 

 tions which appear to favor or retard the develop- 

 ment of certain diseases. Of these, twenty-one 

 are mentioned, — surgical fever and shock after 

 operations, small-pox, measles, whooping-cough, 

 scarlet-fever, typhus, typhoid, intermittent fever, 

 diarrhoea, dysentery, cholera, bronchitis, pneu- 

 monia, asthma, phthisis, diphtheria, hydropho- 

 bia, erysipelas, puerperal fever, insanity, and 

 rheumatism. Small-pox has been found, in London 

 and in Sweden, to prevail more from November to 

 May than from May to November. Measles is most 

 prevalent towards the end of March : it gradually 

 declines, and by midsummer disappears. Diar- 

 rhoea is a summer-autumn complaint, and typhoid 

 a late-autumn fever. The latter is more prevalent 

 after dry and hot summers than after those which 



