lry 9, 1919] 



(IRE 



3 6 9 



Wall es from 250 



per million ;it fifteen years of age to a maxim* 

 2750 per million al forty-seven years of age, after 



which il steadily declines to 500 per million al eighty 

 years g almost symmetrical. 



For London the curve is much the same, though 

 steeper, because the maximum death-rate is 

 higher, being 4500 per million at fifty yeai 

 age. Lancashire and Staffordshire show .1 very 

 similar curve. If, however, we lake the figures 

 for North Wales for males for the same pi 

 (1901-10), the death-rate rises abruptly from 500 



million at fifteen years of age to 2800 

 million at twenty-three years of age, continues at 

 about this level up to fifty years of age, then rises 

 slightly up to sixty years of age, and then declines 

 (the curve for Norfolk is much the same). The 

 curves for London and for North Wales are thus 

 utterly different. Cornwall shows a well-marked 

 secondary rise, and the form of the curve is the 

 same whether the tin-miners, who are specially 

 prone to phthisis, be included or not. For this 

 county the phthisis death-rate rises to about 2600 

 per million at thirty ye; . declines to 1300 



per million at forty years of age, rises again to 

 3250 at sixtv years of age, and then falls. 



Similar differences are met with in Scotland. 

 The phthisis death-rate among males in Shetland 

 for the years 1881-1900 rises steeply to 6000 per 

 million at twenty-three years of age; it then falls 

 almost regularly to 1500 per million at fifty years 

 of age, and continues at about this level until 

 seventy is reached. For Midlothian, including 

 Edinburgh, on the other hand, the curve is very 

 similar to the London one, with a maximum death- 

 rate of 3750 per million at 42.I year< 

 age. For Ireland the curve is not unlike the Shet- 

 land one, a maximum death-rate of 4500 per 

 million being attained at twenty-seven years of 

 age, with the exception that it declines almost 

 regularly to 500 per million at seventy-five. 



From these and other data the conclusion is 

 arrived at that phthisis or consumption of the 

 lungs is not a single disease, but rather a group 

 of diseases, of which one type attacks the young 

 adult, the commonest age of death lying between 

 twenty and twenty-five; a second type has 

 its incidence at middle life, killing most com- 

 monly between forty-five and fifty, while a third 

 type may exist, but less certainly distinguished, 

 with its 1 hief mortality between fifty-five and sixty- 

 five, !n diseases such as cerebro-spinal fever and 

 pneumonia four or five different races or varieties 

 of the respective specific micro-organisms are now 

 known to exist, and the results of this statistical 

 inquiry suggest that something of the same nature 

 may obtain as regards the tubercle bacillus of 

 pulmonary tuberculosis or phthisis. In the intro- 

 duction to the report it is stated that the bac- 

 teriologist has not yet discovered "type" differ- 

 ences among the human tubercle bacilli of 

 phthisis. This- statement is not altogether correct, 

 for certain observers have arrived at the conclusion 

 that there are at least two types of the human 

 tubercle bacillus of phthisis with distinctly dif- 

 NO. 2567, VOL. I02] 



ferent properties, which may be differentiated by 

 certain methods. Other matter of considerable 

 interest is also included in the report, viz. an 

 examination of the phthisis death-rate in London 

 since 1631, the relationship of phthisis to certain 

 occupations (among tin-miners the death-rate is 

 16,500 per million at fifty to fifty-live, while among 

 coal-miners it never rises above 2000), and the 

 relationship of phthisis to environment. The 

 report is illustrated with twenty-six diagrams 

 showing the phthisis and other death-rates in 

 graphic form, which give a far better idea than 

 words could do of the variations alluded to above. 

 R. T. Hewlett. 



NOTES. 



I"hi rs .who have bun advocating the 



ric drive of ship propellers will read with mixed 

 announcement made on January 2 bv Mr. 

 Daniels, the Secretary of the U.S. Navy, that in the 

 future all the capital ships of that Navy will be elec- 

 trically driven. There is no reason to doubt that the 

 new American Dreadnought — the New Mexico — is a. 

 success. Steam turbines are used, and in order 

 to get their highest efficiency they must be kept 

 running at high speeds. The ship's propellers run at 

 much lower speeds, and so direct driving is out of 

 the question. The turbines are directly coupled to 

 dynamos, and the electric power generated is trans- 

 mitted to motors directly coupled to the propellers. 

 The relative speed of the turbines and the shafts can 

 bi adjusted to any desired value with the greatest 

 by merely turning the controller-handle. The 

 experiments undertaken in this country a few years 

 ago were carried out in a timid and hesitating wav 

 both from the engineering and the financial point of 

 view, and the results were generally disappointing to 

 the electrician designers. It is possible, but bv no 

 means probable, that slow-speed turbines mav be 

 developed in the future. In the meantime, we hope 

 that British shipbuilders will make larger use of the 

 1 'i trie drive in the future than thev have in the past. 



The Times for January 3 announces that the world's 

 altitude record has been broken by a British biplane, 

 which flew from Martlesham Heath and attained a 

 height of 30,500 ft.- — 1500 ft. higher than the summit 

 of Mount Everest. The machine was piloted by Capt. 

 Andrew Lang, R.A.F., with Lieut. Blowes as ob- 

 server, Capt. Lang having previously made two 

 attempts to beat the American record. It is of con- 

 able interest to note that the height attained was 

 limited by the failure of petrol-pump pressure, due to 

 the raritv of the air, and not by the aerodynamic 

 performance of the machine. The machine was fitted 

 with a Napier Lion engine, but it is not stated whether 

 forced induction was employed to keep up the engine 

 power at this enormous altitude, where the air density 

 is only 28 per cent, of its ground value and the tem- 

 perature of the order — 40 ° C. It would appear, how- 

 ever, that even greater heights could be reached if 

 minor difficulties, such as those connected with car- 

 liuration at low temperatures and the maintenance of 

 the pilot's comfort, were overcome. Meanwhile, it 

 i tying that ' : bould be held bv British 



aviators, and we hope that it may continue to bi 

 the future. 



President Wilson has n a most cordial 



reception in Rome during the pasl few days. He has 

 been admitted a membei ci ademia dei 



