;66 



NA TURE 



[September 9, 1922 



Experimental Silicosis of the Lungs. — It is 

 well known that the inhalation of dust particles in 

 various industries may be provocative of serious 

 fibrotic and other changes in the lungs. This obtains 

 particularly among grinders, file-makers, and clay 

 workers, while other dusts, notably coal dust, are 

 much less harmful. The miners on the Rand suffer 

 much from silicosis, due to the inhalation of silica 

 particles derived from the quartz, and A. Ma.vrogor- 

 dato has investigated the question experimentally 

 by causing guinea-pigs to breathe dust-laden air of 

 various kinds over varying periods (Publications of 

 the S. African Institute for Medical Research, No. xv. 

 192). He finds that the solubility and chemical 

 activity of dust, e.g. silica, are the important factors 

 inducing fibrotic changes in the lungs, hardness and 

 sharpness of the particles being of little importance. 

 The majority of the particles entering the lungs are 

 less than i/x in diameter. The particles do not 

 penetrate the tissues, but the tissues take up the 

 particles by means of phagocytic cells. The silica- 

 laden cells block lymphatics and thus prejudice the 

 lungs' ability to deal with infections, and hence 

 secondary tuberculous infection is common. 



The Bacterial Flora of Greenland. — Samples 

 of the soil and of the faecal matter of polar animals 

 collected by Dr. T. Wulff in North Greenland in 1916 

 and 191 7 were examined bacteriologically by Dr. C. 

 Barthel in Copenhagen. Nineteen species of bacteria 

 were isolated from the soil and identified. They 

 included such well-known forms as B. subtilis, S. 

 fiava, B. mesenlericus, and B. zopfii. Almost all the 

 soils contained nitrates, and in some, nitrifying micro- 

 organisms were detected. In addition, denitrifying, 

 ammonising, urea-fermenting, and butyric forms were 

 found. In the faecal matter of such animals as the 

 blue fox, arctic hare, crow, seal, polar bear, lemming, 

 and white partridge a variety of aerobic and anaerobic 

 organisms was isolated, including M. candicans, Strep, 

 facalis, B. putrificus, and others. The results obtained 

 indicate the ubiquity of many species of bacteria, 

 both simple saphrophvtes of the soil and of the animal 

 intestine, and special putrefactive and nitrifying 

 forms. (Recherches bacteriologiques sur le sol et 

 sur les matieres fecales des animaux polaires du 

 Greenland Septentional. Den II. Thule Ekspedition 

 til Gr0nlands Nordkyst 1916-18. Nr. 1. Copenhagen, 

 1922.) 



Precipitation in the United States. — A notice 

 of the new . precipitation section of the Atlas of 

 American Agriculture is given by Prof. Robert De 

 C. Ward in the U.S. Monthly Weather Review for 

 March. Notice has previously been given of the 

 monthly, seasonal, and annual rainfall charts, but 

 the fresh material to complete the precipitation 

 section has recently been sent in the form of loose sheets 

 to some to whom the material is of immediate practical 

 use, prior to the final issue. The records are for a 

 uniform period of 20 years, 1895-1914, from about 

 1600 stations, and in addition shorter records are 

 used from about 2000 other stations. The object 

 of the publication is to benefit agriculture, and it 

 lays marked emphasis upon the departures which 

 may be expected from the average, so that the farmer 

 may decide for himself what crops he may plant with 

 the greatest probability of success. Numerous charts 

 and graphs are given. The percentage of the annual 

 precipitation occurring between April 1 and September 

 30 is highest, more than 70 per cent., over most of the 

 great agricultural region of the eastern United States, 

 embracing the eastern Plains and Prairie States. 

 Frequency and intensity of precipitation are shown 



NO. 2758, VOL. IIO] 



in great detail for the whole country. Day and night 

 rain percentages are separately given, and it is shown 

 that over the great agricultural states east of the 

 Rocky Mountains large sections receive more than half, 

 and considerable areas receive about two-thirds of 

 their warm season rains at night, and there is therefore 

 much less rapid evaporation. Snowfall is considered, 

 and the annual number of days with thunderstorms, 

 and the distribution of fog and cloudiness are given. 



The Standard Atmosphere. — In aeronautical and 

 artillery calculations it is now necessary to know the 

 condition of the atmosphere at heights up to 20 kilo- 

 metres with a degree of accuracy not previously 

 required, and each nation is at present concerned to 

 define a mean condition from which the actual con- 

 dition within its borders at any time will deviate only 

 by relatively small amounts. It has been found 

 that Toussaints's formula t - 15 =o-oo65z, where z 

 is the altitude in metres, gives the mean temperature 

 throughout the year up to 10 kilometres, above which 

 the temperature is constant at - 55 C. The observa- 

 tions in the United States set on foot by the American 

 National Advisory Committee for Aeronautics have, 

 according to Report No. 147, prepared by Mr. W. R. 

 Gregg, established the applicability of the formula 

 to that country. The report also shows that the 

 hypsometric equation based on Toussaints's formula 

 leads to values of the pressure in agreement with 

 observations, and that the density at any level may 

 be calculated from the pressure and temperature by 

 the " perfect gas " equation. 



Sensitisers for the Extreme Red. — In the 

 British Journal of Photography for August n, Drs. 

 1 E. K. Mees and G. Gutekunst describe three new 

 sensitisers for the extreme red, giving their properties 

 and methods of preparation. They are suitable either 

 for adding to the emulsion or for bathing ready pre- 

 pared plates, with the exception noted below. Beta- 

 naphtha-cyanole gives a strong maximum at 690 n /j., 

 and sensitises the green markedly less than pinacyanol. 

 Acetamino-cyanole added to an emulsion gives a 

 strong maximum at 730 m a< ; but in dilute aqueous 

 solution as prepared for bathing plates it appears that 

 the acetyl is hydrolysed off, and its effect is much 

 restricted. Kryptocyanine gives a very strong 

 maximum at 760 fi m, and even at 850 /j. m its sensitising 

 power is greater than that of dicyanine, but beyond 

 this point dicyanine is the more advantageous, and 

 at 900 fi.fi kryptocyanine is almost useless. It does 

 not sensitise in the green, and therefore may prove 

 to be of special value in astronomical photography. 

 On account of their peculiarly advantageous proper- 

 ties, naphthacyanole and kryptocyanine will be added 

 to the list of sensitisers prepared and supplied by 

 the Research Laboratory of the Eastman Kodak 

 Company. 



Canned Foods. — The Food Investigation Board 

 has issued a special report (No. 10, is. 6d. net) on 

 methods used for the inspection of canned foods 

 (Part II., Canned Marine Products), compiled by Dr. 

 William G. Savage. Attention is directed to the want 

 of uniformity in procedure adopted by food inspectors. 

 Much experimental work was carried out, but no 

 tests wire evolved more trustworthy than those in 

 vogue for distinguishing swiftly and accurately be- 

 tween the safe, the dubious and the unfit tins. A 

 ' ' blown " tin is clearly a bad tin, but a tin with an 

 abnormal shake sound or a springy top or bottom is 

 merely a suspect sample. An organisation is sug- 

 gested whereby better results and greater uniformity 

 of inspection of canned foods might be obtained. 



