Dec. n, 1SS4I 



NA TURE 



141 



officers of health, and 996 inspectors of nuisances, all of whom 

 are expected to get their information and to acquire the techni- 

 cal knowledge of which they stand daily in need as best they 

 can ; and it is well known that a large proportion of them are 

 very imperfectly equipped with the necessary knowledge, and 

 indeed can hardly be said to possess even the rudiments of 

 systematic technical education in subjects in which they are 

 presumed to be experts, and which they are called upon to decide 

 in matters largely affecting the pockets of the community and 

 intimately concerning its health. In order to illustrate the import- 

 ance of the establishment in this country on a permanent footing 

 of such laboratories as those which were shown in temporary 

 working at the Exhibition, I shall a^k leave now to refer you 

 to an exhibit which was made in the French Court, illustrating 

 the work done by M. Pasteur in a similar laboratory to that of 

 which I am now advocating the permanent establishment, as 

 the best possible sequel of this great Exhibition. 



M. Pasteur is the scientific director of the Ecole Normale 

 superieure in Paris, a school especially designed to supply pro- 

 fessors in literature and science to the lycees or higher schools of 

 France. He is not, however, called upon to undertake teach- 

 ing, but is expected to devote all his time to his researches. In 

 a word, in consideration of the considerable national services 

 which he has rendered, an exceptional position has been accorded 

 to him. He receives a professorial salary of 400/. a year. 

 ur is also the head of 1'Ecole des Hautes Etudes, of 

 which Mr, Chamberlain is the sub-director. In this laboratory 

 lie receives some pupils. He possesses further a laboratory at 

 the Ecole Normale, where M. Roux is his coadjutor, and where 

 are admitted some students who are generally persons already 

 known for their studies. He has entire freedom of the choice 

 if students of the laboratory of 1'Ecole des Hautes Etudes, as well 

 as those of persons who work in his private laboratory at the 

 I ole Normale. About 800/. a year are allowed for this 

 laboratory by the Minister of Public Instruction, and for the 

 last few years, 30,000 francs from the Minister of Commerce 

 and Agriculture. These grants are renewed yearly. 



The principal researches of M. Pasteur have related to — 



1 1) (Vine, in which he demonstrated that, in order to avoid 

 the transformation of alcohol into acid, it is necessary to destroy 

 the germs remaining in wines which are poor in alcohol, by 

 heating them up to 55°'°°° Centigrade. He has also studied 

 the action of oxygen and light 011 wine, and has demonstrated 

 that it is to this action, i.e. to the oxidation of the materials of 

 wine, that we are to attribute the development of the bouquet of 

 wine, i.e. the flavour which it acquires with age. In order that 

 this may yield a product appreciated by amateurs, it is necessary 

 that it should proceed slowly. He has further demonstrated 

 that the ferment of wine exists on the surface of the grape when 

 it has ripened. He has demonstrated the useful and precise 

 indications which the areometer furnishes, in order to appreciate 

 during fermentation the state of the mout of the grape. 



(2) Beer. — After having demonstrated that brewers employ, 

 generally, a ferment containing, among others, injnrious germs, 

 M. Pasteur indicates the following means for obtaining a pure 

 ferment. A small quantity of pure yeast is prepared according 

 to the exact rules of the laboratory. This is introduced into a 

 large copper pan, three-quarters tilled with the wort of beer, 

 which has been first carried to the boiling-point, and then 

 cooled before the introduction of the yeast. The vessel only 

 communicates with the external air by a long tube of copper, 

 many times bent, in such a way as to permit the gases to escape 

 without external germs being able to enter. When the wort has 

 been developed, it is drawn oft' by a tap placed in the lower 

 part of the apparatus, and which is previously purified with the 

 flame of a spirit lamp. The wort of the beer is put to ferment 

 in a large white-metal vat, resting on a plank, and closed by a 

 movable cover, this movable lid dropping into a groove which 

 is kept full of water. As the wort arrives in a boiling state in 

 I, it destroys any germs which may exist there. When 

 ii is cooled, and the cooling may be rapidly aided by the use of 

 external cooling water, the yeast is introduced through an open- 

 ing in the lid. The aeration of the fluid is obtained by two 

 tubes curved downwards, by one of which carbonic acid escapes, 

 and by the other the air enters after being previously filtered 

 through a layer of cotton wool rolled round a cylindrical cage on 

 metal wires which cap the extremity by which the air enters. 

 This apparatus, like the foregoing one, reproduces exactly the 

 conditions which are found to be necessary in the laboratory to 



prevent the introduction of external germs. The aeration by 

 these two tubes is sufficient, for the carbonic oxide being heavier 

 than air, they are placed in such a way as to form a siphon ; 

 moreover, during the fermentation, the wort is certainly kept in 

 movement by the ebullition of the gas which escapes, so that 

 the aeration, although less active than in some of the technical 

 apparatus previously in use by brewers, is more than sufficient. 

 By employing this procedure, secondary fermentations are no 

 longer to be feared, and the spoiling of beer by secondary fer- 

 mentation is almost entirely put an end to. 



(3) A third and profoundly interesting series of researches, 

 which have had a great influence on agriculture, carried on by 

 M, Pasteur, are those relating to charbon — the malignant pus- 

 tule or black quarter of cattle and sheep. M. , Pasteur has 

 demonstrated that animals of the ovine and bovine species may 

 be prevented from contracting the disease of charbon by inocu- 

 lating them with attenuated germs, obtained by artificial culti- 

 vation of the specific minute organism which is ascertained to 

 exist in the case of charbon, and to be the efficient cause of 

 the disease. This attenuated preventive material for inocu- 

 lation is obtained by the aid of what are known as cultivations 

 of the germs made in special liquids. After the first inoculation 

 with the highly attenuated virus, Pasteur has shown that the 

 second inoculation may be made with a product of medium 

 virulence, and that the animals thus twice vaccinated were un- 

 susceptible of contracting the disease. Pasteur has further 

 demonstrated that the bacterium of chai hen is capable of retaining 

 its vitality for several years in the earth, and that, when brought 

 to the surface by earth-worms, it is capable of infecting the 

 animals which eat the grass polluted by its contact, especially 

 if the grasses or plants so eaten be hard, and such as to cause 

 abrasions in the mouth and digestive tube. 



(4) Silkworm Disease. — M. Pasteur, after having assured him- 

 self that normally, and in good health, silkworms never contain, 

 at any moment of their life, the bacteria or corpuscles seen for 

 the first time by Guerin Menneville, demonstrated that the eggs 

 of the worms, even when only slightly attacked, contained a 

 great number of these corpuscles or bacteria, which developed 

 in considerable quantities when the animal underwent its meta- 

 morphoses, and finally destroyed it. Since its droppings polluted 

 the leaves of the mulberry on which the silkworm feeds, and as 

 healthy animals thus devoured them, and contracted the same 

 disease, a single infected silkworm was capable of destroying a 

 whole school of worms, and preventing the subsequent cultures 

 from being developed. 



M. Pasteur then laid down the rule that, in order to avoid the 

 silkworm disease, it was necessary to choose with extreme care 

 the animals which were to be employed for breeding. With this 

 view he devised the following procedure : — When the female has 

 laid its eggs it is at once destroyed. If a single corpuscle is 

 found in its tissues, when crushed in water, the eggs are im- 

 mediately burned. In the same way the several eggs of each 

 hatching are carefully examined. If no corpuscles are disco- 

 vered, the whole brood is preserved for culture ; if any are 

 found, the whole are immediately destroyed. Since that time 

 the silkworm breeders have followed the rules of M. Pasteur. 

 The implements for the purpose of recognising the diseased 

 worms consist of a microscope, two objectives, one with low 

 power, and one with high power, magnifying about 400 times, 

 and a small porcelain mortar for crushing the tissues of the 

 worm or its eggs, some glass slides, and a flask of distilled 

 water. By this application of scientific research to the silkworm 

 industry the silkworm disease has been almost wholly put an 

 end to. Nearly all the silkworm growers, whether ma,, ers or 

 servants, have learnt, by the aid of a very cheap little hand- 

 book, prepared by M. Pasteur, to recognise diseased worms or 

 eggs from healthy eggs or worms, and thus a great irdustry, 

 which was threatened with extinction, has been saved from the 

 fate which threatened it. 



(5) Foul Cholera. — After having demonstrated that this 

 affection is caused by a micrococcus, M. Pasteur showed that if 

 this micrococcus is cultivated in the manner which he indicates, 

 and the micro-organism thus obtained inoculated in a fowl, the 

 fowls so vaccinated become proof against 'fowl cholera, even 

 when they are placed in the midst of other infected fowls. These 

 researches have a special and suggestive scientific interest, for he 

 has shown that if you filter through plaster the liquid taken 

 from one of the external foci of the disease in a fowl affected 

 with fowl cholera, the filtered liquid thus inoculated will not 

 give a healthy fowl the specific disease, but render it somnolent 



