October 12, 1905] 



NA TURE 



581 



amount of closed magnetic shells and solenoids. It will 

 thus be seen that even if we take the internal and external 

 sources to be detached, the plain proposition given by 

 Prof. Schuster would appear to require a modifying clause 

 in order to be e.\act. .A. Tanak.4d.4te. 



Physical Laboratory, Imperial University, Tokyo, 

 August. 



A Polarisation Pattern. 



The following may be of interest to some of your readers. 



\ cylindrical mica chimney of an Auer gas-light is placed 

 vertically on a varnished table. If we look through it at 

 the diffused daylight from a window reflected by the table, 

 faint coloured bands are seen running parallel to the length 

 of the cylinder near both edges. If observed through a 

 .Xicol's prism, the band appears very beautiful. 



T. Terada. 



Physical Laboratory, Science College, Imperial 

 University, Tokyo, September 8. 



A hocusing Screen for Use in Photographing Ultra- 

 violet Spectra. 



The sensitive surface upon which Stokes projected the 

 ultra-violet rays when observing metallic lines and absorp- 

 tion spectra consisted of a plate of plaster of Paris 

 moistened with a paste of uranium phosphate acidified with 

 phosphoric acid {Journ. Chem. Soc, vol. xvii., 1864). 

 -Soret used uranium glass and solutions of fluorescent sub- 

 stances such as a'sculine in liquid cells. I have found 

 that the most convenient and effective screen for examining 

 spectra with a quartz spectrograph is one such as is used 

 for the X-rays. It may be made as follows : — a photo- 

 graphic plate is first cleared of silver bromide by fixing 

 and washing, and when the film is partly dry, but the 

 gelatin still soft, it is dusted over with a powder of 

 barium platinocyanide crystals, so as to be somewhat 

 thickly coated with the salt. This is fixed in the dark 

 slide of the camera. To focus a spectrum, the slide is 

 tilted to the necessary angle, and a somew-hat powerful 

 focusing glass with a flat field is applied to the uncoated 

 surface of the plate, when both the visible and ultra-violet 

 spark spectra may be plainly seen by transmission, the 

 latter by reason of the fluorescence e.xcited. The focusing 

 glass should be first carefully adjusted for any visible 

 object on the other side of a plain glass plate, such as a 

 fine hair fastened upon it, and the position of the eye- 

 piece is then fixed. Suitable focusing glasses are those 

 made by Dallmeyer and by Taylor, Taylor, and Hobson. 

 When the spectrograph has been adjusted by means of the 

 screen, the ultra-violet lines appear quite as sharp as those 

 in the red and yellow, even the details in the group of 

 cadmium lines between wave-lengths 2100 and 2400 are 

 well defined, and a very fair photograph may be obtained ; 

 but for the most accurate focusing photography must be 

 resorted to. \V. N. Hartley. 



Royal College of Science, Dublin, October 2. 



Tne Omission of Titles of Addresses on Scientific 

 Subjects. 



The published reports of the British Association make 

 .HI omission of an equal and opposite character to that about 

 which your correspondent complains. Perhaps these are 

 intended to cancel out. I refer to the publication of titles 

 only, without any text. On receiving the last report 

 (1904, Cambridge) I analysed this matter so far as it 

 relates to Sections A and G, in which I am most interested. 

 In Section A there were 83 communications, 29 of which 

 appear by title only, and of these publication elsewhere is 

 referred to in foot-notes in 4 cases, leaving 25 to the 

 recollection of the audiences who heard them. Section G 

 was better. There were 25 communications, and 13 

 appeared by title only ; but of these 9 may be traced by 

 those who take the trouble to consult the other publications 

 referred to in the foot-notes. A. P. Trotter. 



Westminster, October x. 



NO, 1876, VOX . 72] 



THE INTERNA TIONAL CONGRESS ON 

 TUBERCULOSIS. 



'PHE International Congress on Tuberculosis, held 

 -*• in Paris on October 2-7, has undoubtedly served 

 as a medium for a most fruitful interchange of views 

 by those interested in the struggle against tuberculosis. 

 The congress was held in the Grand Palais, which 

 Irom its extent enabled the members to be collected 

 under one roof. The first day was devoted to the 

 formal opening, when the delegates were welcomed 

 by the President of the French Republic, who also 

 after the close of the congress gave a reception at 

 the Palais de I'Elys^e. The chief social functions, 

 which were characterised by complete success, com- 

 prised a reception at the Hotel de Ville by the Munici- 

 pality of Paris, an " at home " by the Figaro, at 

 which performances were given by well known 

 artistes, a soiree at the Hotel Contiiiental given by 

 the president of the congress, Dr. Herard, another at 

 the Chatelet Theatre by the Matin, and a visit to 

 \au.x de Cernay on the invitation of Dr. Henry de 

 Rothschild. 



The British Government was represented by Dr. 

 Theodore Williams and Dr. Bulstrode, the National 

 .Association for the Prevention of Consumption by Sir 

 William Broadbent and Dr. Perkins, while the foreign 

 Governments and all the leading medical societies and 

 institutioris had their special official representatives. 



The chief feature of the congress was reserved for 

 the closing seance, when Prof. v. Behring announced 

 that he had every reason to hope he had discovered 

 a method of treating tuberculosis which would be as 

 efficacious as the anti-toxin treatment of diphtheria 

 he had first proposed in 1890. 



His statement, received with great enthusiasm, was 

 to the effect that, although he had made a great step, 

 the value of his proposed procedure must be tested 

 on animals in other laboratories than his own, and 

 clinically by physicians with an intimate knowledge 

 of the varieties of pulmonary tuberculosis, before it 

 could be said that an actual curative medium had been 

 found. 



Prof. Behring, as had been anticipated, gave no 

 exact details as to tne method of obtaining or 

 administering his latest therapeutic discovery, but the 

 earlier stages of his work are to be explained in a 

 forthcoming book entitled " Modern Problems of 

 Phthisiogenetic and Phthisiotherapeutic Physiology 

 illuminated by History." 



His experiments have led him definitely to abandon 

 the idea of introducing living tubercle bacilli into the 

 human body with a therapeutic object. He has dis- 

 covered a substance, to which he has given the name 

 T.C., which represents the vital principles of the 

 tubercle bacillus of Koch. To the presence of this 

 substance, which possesses extraordinary fermentative 

 and catalytic properties, is due both the hypersensi- 

 bility of living organisms to Koch's tuberculin and the 

 protective reaction against tuberculosis. This T.C. 

 impregnates and becomes an integral part of the cells 

 of any organism with which it comes in contact, 

 undergoing a metamorphosis into another substance 

 to which the name T.X. has been given. 



This elaboration of T.C. in the organism is a long 

 and perilous process. Prof. v. Behring claims to have 

 succeeded in producing this change iti vitro by freeing 

 the T.C. from certain substances which impair its 

 therapeutic action. Of these he distinguishes three 

 groups : — (i) a substance (T.V.) only soluble in pure 

 water, and possessing a fermentative and catalytic 

 action. To the presence of this substance are due the 

 toxic effects of Koch's tuberculin. One gram of this 

 in the dry state is more toxic than a litre of the old 



