NA TURE 



[July 25, 1901 



The Secretary General in his opening report referred 

 to the Pathological Museum as one of the chief educa- 

 tional works of the Congress, and there can be little doubt 

 that no such collection of tuberculous specimens has 

 ever before been brought together. Every known tuber- 

 culous lesion in man and in the lower animals is illus- 

 trated, and every bacillus that in the smallest degree 

 resembles the tubercle bacillus is represented. Classical 

 specimens of Potts, Addison and Astley Cooper are all 

 shown, and of specimens of later date a really typical 

 collection has been made. After other features in the 

 history of the Congress had been alluded to by the 

 .Secretary General, the Congress was declared open and 

 a telegram was sent to the King. An answer to this 

 telegram, wishing the Congress all success, came before 

 the close of tlie meeting. The delegates were then 

 addressed by the Marquis of Lansdowne, Earl Cadogan, 

 the Lord Mayor of London, Lord Strathcona and Lord 

 Lister, whose remarks are reported by the Times as 

 follows ; — 



He said they met under immeasurably happier auspices than 

 could possibly have been the case not many years ago. Thanks 

 to the labours of the illustrious man who would address the 

 general meeting on the following day, they now knew the enemy 

 they had to deal with, which before the discovery of the tubercle 

 bacillus was shrouded in impenetrable obscurity. They also 

 knew, thanks to Pasteur, that that microbe was incapable of 

 originating de ncr.'o in the human body ; that, while some con 

 stitutions were more prone to its invasion than others, it musi 

 always be derived from similar organisms in the external world 

 Hence there came to be opened up the splendid prospecl 

 of the prevention of tuberculosis. But it was by no mean^ 

 only prevention that they were looking at. They also 

 aimed in the present day at the cure of consumption. In 

 this respect matters were very much more hopeful than they 

 had been till quite recently. The physician might learn 

 a great deal in this point of view from the experiences of the 

 surgeon. There were a great many surgical complaints which 

 they now knew to be ju.st as much tubercular as pulmonary 

 consumption — that was to say, they were just as much due to 

 the growth of the tubercle bacillus. Vet the surgeon knew that 

 in many of these cases the disease might be completely cured ; 

 that, in consequence of the means — of which they were getting 

 to know more and more every day — which the animal organism 

 had of resisting microscopic invaders, the tubercle bacillus was 

 not only arrested in its progress, but swept away altogether, 

 and the result came to be a healthy state of the tissues and parls 

 in which it was. These experiences showed that tuberculosis 

 was not necessarily an incurable disease. That was an immense 

 point to have demonstrated. Thus, they were not surprised to 

 learn that physicians were coming to look upon the cure of con- 

 sumption more hopefully than they used to do, by treating it on 

 recognised principles and on the same broad, general lines as 

 surgical tuberculosis. For his own part, as a surgeon, he had 

 had cases of pulmonary disease brought but little under 

 his notice; but he had been surprised, even in his limited 

 experience, at the numerous cases among his own patients 

 in which people who many years ago had consumptive 

 lungs had subsequently become free from all traces of the 

 disease and had lived healthy, robust and useful lives. These 

 cases he ventured humbly to regard as cases of cure of con- 

 sumption. Then there were attempts now being made by the 

 use of various specific means to deal with consumption even in 

 its more advanced forms. He must not refer to that at the 

 present time further than to say that some of them at least had 

 very promising aspects. They might be sure that these means 

 would be most carefully considered by the Congress, and he 

 need not say how cordially he hoped and anticipated that their 

 deliberations would be fraught with good. There was another 

 point in which he believed the Congress would be useful besides 

 the concentrated wisdom of the eminent men who had come as 

 delegates to take part in it. If the prevention of tuberculosis 

 was to be effectively carried out, the general public must aid the 

 physician and the surgeon in the endeavour. He anticipated that 

 that splendid gathering of scientific men from all parts of the 

 world, meeting under Royal patronage, for which he might 

 venture to express their profound gratitude, would indicate to 

 he public the vast importance of the work they were engaged 



NO. 1656, VOL. 6x\ 



in and would lead to their cooperation in the endeavour to 

 minimise and -possibly eventually to stamp out entirely the 

 greatest scourge of the human race. 



Some idea of the standing of the delegates may be 

 gathered from the following list of those who were pre- 

 sented to H.R.H. the Duke of Cambridge, and who 

 spoke, each on behalf of his nation : — Prof Osier, from 

 the United States of America : Prof von Schrdtter, 

 Austria ; M. le Senateur Montefiore Levi, Belgium ; 

 Prof Charles Gram, Denmark ; Prof lirouardel, France ; 

 Prof von Leyden, Germany ; Prof. Thomassen, Holland ; 

 Prof. Frederic Koranyi, Hungary ; Sua Eccellenza 

 Senator Enrico di Rienzi, Italy ; Prof. Holmboe, Nor- 

 way ; Prof Cortezo, Spain ; Prof Hofmarshal Printzs- 

 jold, Sweden : Dr. Louis Secretan, Switzerland. Greece 

 and Roumania were also represented, as well as the 

 Universities and all the medical societies and public 

 health bodies in the kingdom. 



The work of the Congress has been arranged in 

 four sections. In the first all questions concerning the' 

 relations of the State and municipalities to the pre- 

 vention of tuberculosis are to be discussed, and if the 

 number of papers announced is any criterion, little should 

 remain undiscussed at the conclusion of the Congress. 

 The second section deals with medicine, including clima- 

 tology ; the third with pathology, including bacterio- 

 logy ; and the fourth with tuberculosis in animals. 



In addition to the purely sectional work, three general 

 addresses will be given. The first of these, by Prof. Koch, 

 of Berlin, dealing with the preventive measures to be 

 taken in connection with tuberculosis, is printed in full in 

 this number ; Prof Brouardel, of Paris, will give the 

 second address : and Prof McFadyean, of the Royal 

 \''eterinary College, the third. Prof. Koch is also an- 

 nounced to open a discussion on tuberculin — a discussion 

 that should be of a very interesting character. 



The " social " programme is unusually attractive, but 

 in no way interferes with the efficient working of the 

 important or business meetings of the Congress. We 

 shall watch with interest the further proceedings of the 

 Congress. 



THE LIOVEFACTTON OF HYDROGEN. 

 'T^'HE liquefaction and solidification of hydrogen form 

 ^ the last of the definite stages, so far, in the progress 

 towards the absolute zero of temperature. To make the 

 account of this stage clear, it will be necessary to compare 

 it briefly with those which preceded' it. 



During the third decade of the last century, Faraday 

 found that, whereas different substances have different 

 boiling-temperatures at ordinary pressure, or different 

 condensation-pressures at ordinary temperature, the 

 lowest Ijoiling point could be lowered further by reducing 

 the pressure artificially. Thus by exhausting with a 

 vacuum-pump the vapour from a vessel containing solid 

 carbonic acid, he was able to obtain cold intense enough 

 to liquefy a large number of gases exposed to the low 

 temperature and, at the same time, to considerable pres- 

 sure. This may be called the vaporisation method ot 

 cooling. Pictet in 1S77 showed how its effect might be 

 intensified by using the cold so obtained by the low-pres- 

 sure boiling of one substance, such as sulphur dicxide, to 

 condense at high pressure some more volatile gas, such 

 as carbonic acid, the subsequent boiling of which at 

 reduced pressure would produce a further reduction of 

 temperature. The successive falls of temperature obtained 

 in this way have caused this to be known as the cascade 

 system of refrigeration. Pictet himself thought that by 

 this means he succeeded in liquefying and solidifying 

 hydrogen, and, though this was probably a mistakej the 

 method has proved a very useful one. By the choice of 

 more suitable substances, carbonic acid and ethylene, 



