October 3, 1907] 



NA TURE 



571 



by Prince Heinrich and the British Ambassador, a 

 banquet, a gala performance at the Opera, concerts, 

 &c., served to make the time pass |)leasaiilly. In 

 addition, visits were organised to all the principal 

 scientific institutions, and were much appreciated. 

 These included the laboratories of the Imperial Board 

 of Health and of the University, the hospitals, san- 

 atoria, schools, &c. It is impossible to do more than 

 glance at a few of the more important communi- 

 cations ; the full papers will be published hereafter in 

 a volume of Transactions. 



There was an important debate on tuberculosis, and 

 some difference of opinion e.\isted as to the most usual 

 mode of infection in man. Prof. Arloing, of Lyons, 

 discussed the question of the existence of different 

 types of the tubercle bacillus. He said that he had 

 become convinced that the bacillus of this disease is 

 but one, and that the species or types described by 

 several observers are but temporary races or varieties, 

 the apparent fixity of which does not survive the con- 

 ditions of their surroundings. He considered that : — 



(1) The types arc rarely defined in a perfect manner; 



(2) they are blended together in an almost indefinite series 

 of individuals which in growth, shape, and virulence 

 .admit of a gradual passage from one to the other ; 



(3) variability is sufficient to explain the usual character- 

 istics of tuberculosis in Mammalia and in birds; (4) there 

 would be real danger, from the medical as well as the 

 hygienic point of view, in making such unstable differences 

 a basis for laying down principles for the prophylaxis of 

 tuberculosis. 



Dr. Ravenel, of Philadelphia, considered that : — 

 (i) The alimentary tract is a frequent portal of entry 

 for the tubercle bacillus. 



(2) The tubercle bacillus is able to pass through the 

 intact mucous membrane of the alimentary tract without 

 producing a lesion. Tbis takes place principally during 

 the digestion of fats. 



(3) The bacilli pass with the chyle through the lacteals 

 and thoracic duct into the blood, which conveys them to 

 the lung, where they are retained largely by the liltering 

 action of the tissues. 



(4) Infection through the alimentary tract is especially 

 frequent in children. 



(5) Milk from tuberculous cows is the source of infec- 

 tion in many cases. Our present knowledge does not 

 enable us to state the exact proportion of cases of tubercu- 

 losis due to this cause, but it is probably considerable. 



Prof. Flugge, of Breslau, said that he had per- 

 forined experiments which showed that tuberculosis 

 could be communicated to animals by inhalation, and 

 that the dose of bacilli required to infect by the 

 respiratory tract was very far less (" millions of 

 times ") than that required to infect by the alimentary 

 tract. The mode of infection in man doubtless varied, 

 and children may be infected by the digestive; tract 

 by tuberculous food, particularly milk, but the most 

 e.xtensive source of infection is the number of droplets 

 of tuberculous expectoration coughed up by consump- 

 tives ; these float in the air and serve as sources of 

 infection to others. Prof. Ribbert, of Bonn, and Prof. 

 v. Schrotter, of Vienna, also from the evidence of 

 autopsies considered inhalation as the chief mode of 

 infection in man. Prof. C'almette, of Lille, believed 

 that in the young, infection by the digestive tract, 

 particularly by tuberculous milk, is the most frequent, 

 and attached little or no importance to dry dust con- 

 taining tubercle bacilli as a .source of infection. 



-Another important discussion w-as on tvphoid and 

 paratyphoid infections of man and the campaign 

 against typhoid fever. Prof. Loffler, of Greifswald, 

 discussed the classification of the causative micro- 

 organisms of these diseases, and their isohition and 

 differentiation by means of sugar nutrient media con- 

 taining a small percentage of the anilin dye 

 NO. 1979, VOL. 76] 



inalachite green. Dr. Lentz, of Berlin, pointed out 

 that the bacteria of typhoid and paratyphoid levers 

 pass by the lymphatics from the digestive tract to the 

 spleen, bone-marrow and blood, and are excreted by 

 the kidneys, in some cases for long periods. Of great 

 importance also are mild cases, sometimes amounting 

 merely to slight indis])i)sili(in ; though the individual 

 may be but little, if at all, ill, he at the s.-ime time 

 e.xcretes the bacillus, and thus may be a source of 

 infection to others. Some of the paratyphoid fevers 

 of man seem to be caused by organisms which pro- 

 duce diseases in the lower animals. .Anti-typhoid 

 inoculation was discussed by Prof. Wright, Col. Leish- 

 man, R.A.M.C., and Dr. Muschold. The latter, from 

 Prussian statistics, considered the method very pro- 

 mising. 



Plague naturally attnicled some attention, and Dr. 

 Giemsa, of Hamburg, discussed the best methods of 

 ridding ships of rats. He preferred to expose the hold 

 to a mixed gas, produced in a generator, consisting 

 of 5 per cent, carbon monoxide, 18 per cent, carbon 

 dioxide, and 77 per cent, nitrogen. Dr. .Strong, of 

 Manila, discussed the subject of preventive inoculation 

 in plague. He considered that this was the mode of 

 combating the disease which held out the most likeli- 

 hood of success, and made out a strong case for the 

 use of living but attenuated cultures of the plague 

 bacillus .as the prophylactic material. Prof. Gaffky, 

 of Berlin, considered the spread of plague to be 

 due primarily to rats, vermin transmitting the bacillus 

 from rat to man. 



In a paper on insects as carriers of disease, Dr. 

 Ddnitz pointed out that tin; ticks .are intermediate 

 hosts of spirocha;la[; and jnroplasmata ; the parasites 

 pass through a developmental stage, and it is not until 

 this has occurred that they can again infect man and 

 animals. He referred to the present lack of know- 

 ledge concerning the structure and developmental his- 

 tory of the ticks, and to the confused noinenclalure 

 of these insects now existing. 



Many papers were devoted to a consideration ot 

 parasitic protozoa. Dr. Dollein discussed the nature of 

 spirochajtes, as to whether they are bacteria or pro- 

 tozoa, and their mode of division. Prof. v. VVasielew- 

 ski, of Heidelberg, believed that all parasitic protozoa 

 can act occasionally .is pathogenic agents. The Leish- 

 man-Donovan body of the Indian disease kala-azar 

 seemed to be a flagellated protozoon ; the piroplasmata 

 also seemed to be allied to the flagellates. Prof. Hew- 

 lett, of London, considered the parasites of the dif- 

 ferent malarial fevers to be distinct species, and the 

 piroplasmata, or some of them, to be more nearly 

 allied to the haemoflagellates thaji to the ha;mo- 

 sporidia. 



The cainpaigns against malaria and yellow fever 

 were fully discussed. Prof. Ross, of Liverpool, gave 

 a hislorv of the institution of anti-malaria measures 

 and of their results in .Sierra Leone, Lagos, Federated 

 Malav .Slates, Pan.ama, and Ismailia ; Prof. .Savas, of 

 .Xtheiis, described the malaria campaign in Greece; 

 and Prof. Celli, of Rom<-, that in Italy. Th<; latter 

 advocated drainage, mechanical means to render the 

 mosquitoes innocuous, c.,?. by the use of netting, &c., 

 and the regular prophylaccic use of quinine. Prof. 

 .Agramonte, of Havana, described the epidemiology of 

 yellow fever and the campaign against the disease in 

 Havana. He considered that the results obtained in 

 the control and extinction of recent epidemics of this 

 disease confirm the truth of the doctrine of mosquito 

 transmission in its propagation. 



Under the heading of dietetics, the subject of the 

 necessary minimum of proteins for alimentation natur- 

 ally came up for discussion. Prof. Korster, of Strass- 

 burg, gave the following as his conclusions : — 



