282 



NATURE 



[January 17, 1901 



alone some 60,000 deaths are recorded annually from tuber- 

 culosis, and it is stated on good authority that at least thrice 

 this number are constantly suffering from one form or another 

 of the disease. The object of the forthcoming Congress is to 

 exchange the information and experience gained throughout the 

 \yorld as to methods available for stamping out this disease. 

 Papers will be read, and clinical and pathological demonstrations 

 will be given ; while the museum, which is to be a special 

 feature of the Congress, will contain pathological and bacterio- 

 logical collections, charts, models, and other exhibits. The 

 address of the General Secretary of the Congress is 20, Hanover 

 Square, London, W. 



Prof. P. K. E. Potain, whose death we regretfully an- 

 nounced last week, at th^ age of seventy-five years, delivered 

 his last lecture on clinical medicine at the Charity Hospital 

 about six months ago. His treatises on diseases of the heart 

 and lectures on clinical medicine are renowned both among 

 physiologists and medical men. Referring to his death at the 

 meeting of the Paris Academy of Sciences last week, M. Marey 

 remarked that Prof. Potain developed the means of diagnosis, 

 and showed how various sounds characteristic of diseases of the 

 heart should be interpreted. Not only was he able to deter- 

 mine with precision any injury or morbid change in the exercise 

 of functions of organs ; he showed also that the disorders them- 

 selves revealed the interrelations between such functions, that, 

 for instance, diseases of the liver and the kidney have echoes in 

 the heart, and that pulmonary tuberculosis prevents the develop- 

 ment of certain cardiac lesions. He was a master of clinical 

 medicine, and an excellent physiologist, as well as a renowned 

 physician. He devised an ingenious colorimetric method for 

 testing certain substances, and his sphygmometei for the measure- 

 ment of arterial pressure is still among the best. Prof. Potain 

 was a member of the Paris Academy of Medicine, a member of 

 the Academy of Sciences, and Commander of the Legion of 

 Honour. 



CuPELLATiON is one of the most ancient of metallurgical 

 processes, and was well known at least as early as the year 

 600 B.C. It was used by the Romans to extract silver from its 

 ores in Spain and at Laurion, but it has been hitherto supposed 

 that the hearths of their furnaces were made of comparatively 

 non-absorbent materials, such as clay and marl, the litharge and 

 other oxides being skimmed off or allowed to flow away in side 

 channels. It is now shown, however, by Mr. Gowland, in a 

 paper read before the Society of Antiquaries in May last, that a 

 silver refinery was worked at Silchester in which argentiferous 

 copper was cupelled on hearths made of bone-ash. Bone-ash 

 has the property of absorbing molten litharge and some other 

 oxides as readily as blotting-paper absorbs water, and apparently 

 only its high cost prevented its use by the Romans in all their later 

 cupellation furnaces. Careful examination of the remains found 

 at Silchester convinced Mr. Gowland that the work there re- 

 sembled some of the operations formerly practised in Japan, and 

 that it is probable that it consisted in the recovery of the silver 

 from Roman copper coins issued m the third century a.d. The 

 metal contained 4 per cent, of silver, and was cupelled in three 

 furnaces in succession with the aid of repeated additions of small 

 quantities of leafl. 



Dr. R. Minervini, of the University of Genoa, has pub- 

 lished recently, in the Zeitschrift fiir Hygiene, the bacteriological 

 investigations he has made of samples of air and water collected 

 in mid-ocean during a trip from Genoa to New York and back. 

 He finds more bacteria in air at sea than did Fischer in his 

 classical investigations. Out of 42 determinations, however, 

 6 }ielded no bacteria, whilst the highest number found in a 

 volume of 27 litres of air was only 17. As was to be expected, 

 he obtained the best results after heavy rain. No pathogenic 



NO. 1629, VOL. 63] 



bacteria were discovered. It is unfortunate that as regards the 

 author's water examinations his stock of apparatus did not 

 permit of his cultivating the samples at once after collection, 

 but compelled him to keep them from seven to ten days until he 

 landed. This fact deprives his quantitative results of their 

 value. The report of the German deep-sea expedition, carried 

 out during 1898-99, is awaited with great interest. It will be 

 remembered that the German man-of-war Valdivia was placed 

 at the disposal of the members by the Government, and it visited 

 the African coasts as well as the Indian and Antarctic Oceans, 

 and bacteriological investigations were included in the work of 

 the expedition. 



The contents of the Cape Agricultural Journal (November 

 22, 1900), which has just reached us, testify to the widespread 

 interest which is being taken in scientific agriculture in Cape 

 Colony. Among subjects dealt with are the liming of soils, 

 selection of seeds, merinos, rhubarb and mealie culture,. 

 " raising" calves without milk, and wide versus narrow waggon 

 tires. The report for 1899 of the Colonial Bacteriologist is 

 also inserted, and in it Dr. Edington describes a method for 

 protective inoculation against horse-sickness, which is 2& 

 follows : — Animals which have passed through an attack of the 

 disease and have recovered are inoculated at intervals with 

 increasing doses of virulent blood taken from affected horses. 

 After this treatment the animals are bled and the serum pre- 

 served. Blood of the highest virulence is likewise obtained, 

 standardised against the serum and preserved. A definite 

 amount of the virulent blood is mixed with 50 c.c. of serum and 

 injected subcutaneously. Some days later 30 c.c. of the same 

 serum, with the same dose of blood, is injected. At a later date 

 the procedure is repeated with a reduced dose of serum, and 

 fourteen days later pure virulent blood is injected. This method 

 is said to afford a perfect and complete solution to the problem 

 of protecting horses which have to live in unhealthy districts in 

 South Africa, and is very similar to that devised by the Imperial 

 Bacteriologist of India against rinderpest, as mentioned in th^se 

 notes on December 13 (p. 161), 



It is to be feared that it will be a long time before the 

 general public realises what is desirable and what undesirable in 

 artificial lighting. The two principal desiderata are well dis- 

 tributed, but not necessarily very brilliant, illumination, and 

 cheapness, which means high efficiency and consequently high 

 intrinsic brilliancy of the source of light : two characteristics in 

 direct antagonism. The use of some form of diffusing shade is 

 therefore desirable, even with the present electric lamps ; and it 

 will be essential when lamps of higher efficiency come on the 

 market, as is sure to occur before long. Mr. W. L. Smith's ex- 

 periments (" A Study of Certain Shades and Globes for Electric 

 Lights as used io Interior Illumination," Technology Quarterly) 

 are a timely and very valuable contribution to our knowledge of 

 the relative merits of various types of shade. For a shade to 

 be satisfactory, it should soften down and distribute evenly the 

 light of the naked lamp, whilst, at the same time, it should not 

 absorb too great a proportion of it. Mr. Smith's experiments 

 show that this problem is solved by very few of the shades in 

 ordinary use. It is worthy of remark that the author finds that 

 the Holophane shades, in which the cutting of the glass is deter- 

 mined on scientific instead of artistic principles, are greatly 

 superior to all others. We have seen a Nernst lamp (w^ich is,, 

 with the exception of the arc, the most intense form of artificial 

 illuminant) burning in a Holophane globe, and can fully en- 

 dorse Mr. Smith's remarks on the excellent manner in which these 

 globes soften and diffuse the light. It is to be regretted that 

 the author has not drawn more distinction between globes de- 

 signed to cover the lamp and shades merely intended to be hung 

 over it, as direct comparison of the two classes is hardly fair. 



