2^4 



THE POPULAR SCIENCE MONTHLY. 



the upper surface of the cuttcr-platc. By 

 this operation a new clean surface is con- 

 stantly produced on the tilter-bcd, practi- 

 cally starting a new filter, at each revolu- 

 tion of the cutter-plate. A model machine, 

 when tried with common sewer-waters at 

 Asnieres, near Paris, having a filter-bed of 

 9i inches in diameter, filtered eight litres, 

 or 1*761 gallons, in a minute under a press- 

 ure of one atmosphere and a half. In the 

 same proportion the rate of filtration with 

 a bed one foot in diameter would be 3"31 

 gallons a minute, and with a bed ten feet in 

 diameter 260 gallons a minute, or 074,400 

 gallons a day of twenty-four hours. Ap- 

 plied to the water-supply of towns, a ma- 

 chine having a filter-bed ten feet in diame- 

 ter should filter, under a pressure of one 

 atmosphere, 466,560 gallons in twenty-four 

 hours. 



Orio;in of Diphtheria. The observa- 

 tions of Mr. G. II. Fosbrooke, medical 

 health-officer of Birmingham, England, 

 have led him to form conclusions respect- 

 ing the etiology of diphtheria which differ 

 in some points from those which have been 

 urged by other authorities. He regards it 

 as a well-established fact, confirmed by his 

 experience, that the disease is more com- 

 mon in rural than in urban districts, and 

 has observed that even when it has pre- 

 vailed extensively in a rural district, and 

 has thence been conveyed into a neighbor- 

 ing town, it has not spread in the town. 

 In one town of five thousand inhabitants, 

 diphtheria, when it occurred, prevailed con- 

 currently with typhoid fever or scarlatina, 

 giving rise to the suggestion that all those 

 diseases might originate in a common poi- 

 son. Mr. Fosbrooke does not agree with 

 other authorities as to the conditions of 

 soil most favorable to the propagation of 

 diphtheria. Generally the disease has been 

 thought to flourish most in damp situations 

 and in connection with damp subsoils. All 

 of his attempts to associate its origin and 

 distribution with any peculiar soil or situa- 

 tion have failed, for he has met it both in 

 villages occupying elevated and airy situa- 

 tions and in low places. The most serious 

 epidemics and the larger number of cases 

 of which he has had personal knowledge 

 have appeared on soils that were '^ rather 



gravelly and well drained." With one ex- 

 ception, his experience opposes the idea 

 that houses shut in by trees are more liable 

 to harbor the disease than those which are 

 not surrounded bv an abundant vecretation. 

 The fluctuations of diphtheria, when it pre- 

 vails for any considerable length of time, do 

 not appear to be influenced by changes of 

 season or by variations of weather. Mete- 

 orological observations, made with reference 

 to this point, differ widely, and furnish no 

 guide to an opinion. The disease is gener- 

 ally found first to break out in October, and 

 to prevail as an epidemic, when it does so 

 prevail, in the winter months, increasing, as 

 is natural with epidemics, during the earlier 

 months of its course, but without regard to 

 the regularity or irregularity of the season. 



Anthropology in Russia. Anthropology 

 has made much progress in Russia. The 

 Imperial Society of the Friends of Natural 

 Science, Anthropology, and Ethnography, 

 founded in 1863, of which Bogdanof is the 

 master-spirit, has done good service in 

 assuming the patronage of investigations 

 among the numerous diverse stocks of whom 

 the Russian nationality is composed, and in 

 encouraging measures to bring the interests 

 of anthropology before the public. The 

 Anthropological Exhibition, which was held 

 at Moscow last summer, had this object 

 prominently in view, and was further in- 

 tended to promote the establishment of a 

 professorship of anthropology, and of an 

 anthropological museum. The collections 

 exhibited and reported upon embraced 

 skulls, skeletons, relics, prehistoric and 

 modern, and articles of various kinds, illus- 

 trating the character, condition, and cus- 

 toms of the ancient and modern inhabitants 

 of the empire. Among the neolithic stone 

 implements from Kazan were hatchets, 

 crossed by a groove in which to fasten the 

 handle, precisely as in the North American 

 hatchets, and arrow-heads, both with and 

 without shafts. Fragments of urns bearing 

 the well-known pack-thread ornament and 

 bronzes of the so-called Tschudic type were 

 shown from the Volga. Filimonof brought 

 from the Caucasus, where he has been dig- 

 ging under the auspices of the society, great 

 bronze whorls, of similar form to those 

 which are met in the Baltic provinces, but 



