Apeil 24, 1903.] 



SCIENCE. 



663 



a forced storage of at least weeks and at best 

 of many months. In natural ice, besides the 

 action of cold, there is another purifying in- 

 fluence, the exclusion of ninety per cent, of 

 the germs by the act of freezing. Under 

 natural conditions the pathogenic germs pres- 

 ent in the most highly polluted stream are 

 comparatively few. Of these few, one tenth 

 of one per cent, may be present in ice derived 

 therefrom. Even these scattered individuals 

 are weakened by their sojourn under unfavor- 

 able conditions, so that it is doubtful if they 

 could produce many, if any, cases of typhoid 

 fever. With artificial ice the case is different, 

 for such ice is made from water frozen solid 

 and, as a rule, quickly consumed. Such ice, 

 therefore, if made from impure water may 

 contain the germs of infectious disease, and, 

 being used quickly after its manufacture, 

 may be a menace to the public health. With 

 natural ice also there must always remain an 

 element of doubt. Polluted ice might be cut 

 at once, and served within a week or two, and 

 sufficient disease germs might persist to cause 

 infection. Yet the authors think such an 

 instance must be very exceptional; and the 

 general result of human experience, the ab- 

 sence of epidemics of typhoid fever traced 

 conclusively to ice; the fact that cities like 

 New York, and Lowell and Lawrence, Massa- 

 chusetts, have used ice of polluted streams 

 and have yet maintained low death rates from 

 tjT^hoid fever, all tend to support the conclu- 

 sion at which they have arrived, namely, that 

 natural ice can rarely be a vehicle of the in- 

 fectious agent of typhoid fever. 



Such results and conclusions as these, com- 

 ing from this high authority, confirming in 

 essential details the work of other investi- 

 gators, as well as extending our knowledge of 

 this important subject, are somewhat reassur- 

 ing in regard to the use of ice. 



This is especially true from the standpoint 

 of the general sanitarian, who, accepting these 

 data, may look upon stored ice as a neglect- 

 able sanitary quantity, and to the statistician 

 in his estimates of usual sources of disease; 

 but in the opinion of the reviewer, the indi- 

 vidual facing the element of doubt in the 

 purity of ice, and especially as ice is so uni- 



versally handled just prior to using, should 

 not be led by the purity of the ice in general 

 to abate any reasonable precautions for his 

 own protection. It has been too much our 

 habit, as many fatal epidemics bear witness, 

 to take chances in matters sanitary, and to 

 bend to expediency and personal or public 

 convenience rather than to strive for the ideal. 



Such papers are apt to convey the impres- 

 sion to the lay and even, it is to be feared, to 

 the official mind, that sanitary precautions 

 may be neglected in the use of ice. Let us 

 urge, however, that it is small comfort to the 

 individual suffering from typhoid fever con- 

 tracted from polluted ice to be told that 

 ninety-nine per cent, of his friends use ice 

 with impunity. 



In the studies of statistics on the seasonal 

 prevalence of typhoid fever in various coun- 

 tries and its relation to seasonal temperature, 

 the authors review fully the literature on the 

 seasonal prevalence of typhoid fever, setting 

 forth at some length the various data as to 

 the time of maximal and minimal occurrence, 

 and the hypotheses that have been advanced 

 in explanation of those variations. Chief 

 among these, historically at least, as is so 

 well known, is the view, supported by Pet- 

 tenkoffer and his school, that there is a rela- 

 tion between the variations in level of the 

 ground water and variations in the prevalence 

 of typhoid — typhoid cases being abundant 

 when the ground water is lowest. The only 

 plausible explanation of the connection, how- 

 ever, between ground water and typhoid fever 

 on the basis of the germ theory is, in the 

 opinion of the writers, that furnished by 

 Liebermeister, who in 1860 suggested that 

 the phenomena might simply be due to the 

 concentration of soil impurities in the wells 

 at the time of low water, and their transmis- 

 sion in unusually large doses to those who 

 drank therefrom. Dr. Baker in this country 

 advocates this idea with modification, and a 

 recognition of the fact that a well in use 

 drains a wider area when the ground water 

 is low and is thus liable to pollution from 

 more distant sources. 



Whatever the explanation, it seems to be 

 true that at Munich in the period studied by 



