be acquired, and in the next five or ten years a sound basis of knowledge of physics, chemistry, and botany, with German or French, might be obtained; and in the following five years anatomy, physiology and medicine, surgery, and midwifery.

If every medical man were thoroughly well educated in the English language, and could explain the nature of the disease and the course to be followed in the most idiomatic and unmistakeable English, and if he could use all the forces in nature for the cure or relief of his patient, and if he could, from his knowledge of chemistry and physics, and their application to disease and medicine, become the best authority within reach on every question connected with the health and welfare of his neighbours; and if he possessed the power of supervising and directing the druggist in all the analyses and investigations which could be required as to the nature and actions of food, drink, and medicines, and as to the products of disease, surely the position and power and agreement of medical men would be very different from that which they now obtain by learning some Latin and less Greek.

At present, so far from physicians possessing more knowledge of food and of medicine than any other class of persons in the community, the analytical and pharmaceutical chemists are rapidly increasing in knowledge, which will enable them not only to understand fully the nature and uses of food and medicines, but even to detect the first appearances of a multitude of chemical diseases. Their habits of investigation and their knowledge of the nature of the forces acting in the body will gradually lead them to become advisers in all questions regarding the health of the community, and from this they will, like M. Bouchardat, in Paris, become almost, if not altogether, practitioners of medicine.

No doubt chemists are very far from being medical practitioners at present, but remember that there is no limit to natural knowledge, and that each moment the chemical knowledge of things around us is progressing, and that chemists are becoming able better to answer every question that can arise regarding the air, water, food, drink, and medicine which, by means of the forces that exist in then, act upon the forces within us, and give rise to the phenomena of health and of disease; whilst, as if to lessen the time that might be devoted to acquiring natural knowledge, the authorities who regulate medical education only this last spring have determined that, in addition to Latin, every medical man shall possess a competent knowledge of Greek, in order that the derivation of hard words may be obtained from the brain instead of a dictionary.

In confirmation of my opinion of the direction in which the treatment of disease is progressing, I may just refer to the cattle-plague, which in 1745 was treated by Dr. Mortimer, at that time Secretary of the Royal Society, and therefore one of the most scientific physicians in the country, with antimony and bleeding. In 1866, two chemists, Dr. Angus Smith, Ph.D., F.R.S., and Mr. Crookes, F.R.S., gave the only useful suggestion for combating the disease, namely, by the arrest or the destruction of the poison by chemical agents.

There is yet another point of view in which chemists will see the harm that results from our present medical education.

The use of Latin in our prescriptions requires that the pharmaceutists should learn at least sufficient Latin to read what we have written. Many errors have arisen, and will arise from the dispenser being unable to give the directions rightly. To avoid such mistakes, a portion of the time that ought to be given to the attainment of the highest possible amount of chemical acquirement, and a perfect knowledge of the English language, or some foreign language, wherein he might learn the discoveries in chemistry, and the improvements in pharmacy of other countries, must be devoted to the learning of Latin in which the physician writes his

directions.

All our druggists in England ought to be what they are in Germany and in France, chemists capable of any analysis that might be required of them, and able to satisfy themselves and the medical men that the substances they sell are what they profess to be, pure, unadulterated chemical compounds.

No one of my hearers in this Section will consider five years a long time for the

acquirement of such knowledge, and until the pharmaceutists all obtain this education, medicine will be subject to a great cause of uncertainty in the variations in the quality and quantity of the different substances which, under the same name, are obtained from different druggists.

Before I conclude I must apologize to some in this Section who may think that this subject is of no interest to them, by reminding them that none but chemists can judge what the worth of chemical education really is; and I am sure that no body of scientific men exists who are so fitted to judge of the necessity of an education in natural knowledge for those who employ the forces around us to regulate the forces within us as the Chemical Section of the British Association.

Last year Professor Miller said, "It behoves all who are themselves engaged in the pursuit of science to consider in what way they can themselves aid in forwarding the cultivation of natural knowledge."

I ask you, for the good of science and for your own good, to exert your influence in the first place, and more especially to effect a change in the preliminary education of all those who intend to practise medicine; so that leaving Greek and Latin to be the ornaments and exceptions in their education, they may have time to obtain the best possible knowledge of the chemical and physical forces with which they have to deal. I urge this because of my conviction that whenever the most perfect knowledge of chemistry and physics becomes the basis of rational medicine, then, and not till then, medicine will obtain the highest place among all the arts that minister to the welfare and happiness of man.

On the Assay of Coal, &c., for Crude Paraffin Oil, and of Crude Oil and Petroleum for Spirit, Photogen, Lubricating Oil, and Paraffin. By Dr. J. ATTFIELD, F.C.S., Director of the Laboratory of the Pharmaceutical Society. The paper included descriptive details of the methods of examining small specimens of coal, shale, lignite, &c., with the view of determining their value as sources of crude paraffin oil. It also contained instructions whereby to obtain the value of a specimen of crude oil or of petroleum as sources of spirit, photogen, lubricating oil, and paraffin. The author placed no dependence on the process of igniting the coal, &c. in a crucible and taking the amount of volatile matter yielded as an indication of the value of the specimen. He preferred to submit the coal at once to distillation, with certain precautions, in a small iron retort arranged in a peculiar manner. After showing how to best separate and weigh the oil and other products of the distillation so as to avoid loss, the author proceeded to suggest the adoption of uniform operations to ascertain the value of the oil or petroleum. These were mainly operations of fractionation with or without previous distillation, with or without previous purification. The separation of paraffin on the analytical scale of the laboratory was then described, the paper closing with suggestive remarks concerning the nomenclature of the various products.

On the Action of Chlorine on Amylene. By Dr. BAUer.

On the Purification of Terrestrial Drinking Waters with Neutral Sulphate of Alumina. By ALFRED BIRD.

The principle upon which this process is founded is based upon the known affinity which hydrated alumina has for organic matters, in combining with them and rendering them insoluble.

The action is as follows:

One part of neutral sulphate of alumina in solution is added to seven thousand parts of the water to be purified. As soon as the mixture is made, a cloudy haze is seen in the water, which haze rapidly condenses into flocculi, with little lanes of clear water of the greatest brilliancy and beauty between them. As the flocculi become more dense they rapidly descend to the bottom of the water, leaving it absolutely free from all organic colouring-matter, as clear as crystal, and free from taint.

The time required for complete precipitation is from six to eight hours; if, there1866.

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fore, the precipitant be put in over-night, the water will be ready for use in the morning, and as time for the action to take place, and not quantity of water is the consideration, ten thousand gallons can as quickly be purified by this process as a gallon.

The chemical action is thus:-The lime which is in solution in the water as a carbonate combines with the sulphuric acid of the sulphate, and forms sulphate of lime. The liberated hydrate of alumina instantly attacks the organic matter, which it renders insoluble, and both rapidly descend to the bottom of the water, while the carbonic acid gas which remains in the water imparts to it a sparkling freshness and beauty.

As the liberation of the hydrated alumina depends on the presence of carbonate of lime in the water, and as its absence in terrestrial waters is a most rare occur rence, the applicability of this precipitant for the purification of terrestrial waters may be said to be universal.

In order to test the effect of the precipitant upon very dirty water, a gallon was taken out of the Thames at half-tide, in the centre arch of London Bridge. Into this water was put twenty drops of a standard solution of the precipitant. The water was then allowed to stand eight hours, when it was found that all the filth had settled to the bottom, and the supernatant water was clear, sparkling, and pleasant to drink.

The author has therefore the greatest confidence in recommending the precipitant for purifying the water contained in ships' tanks, and the waters taken from tropical rivers and ponds, which in their natural state it is impossible to drink, in consequence of the decaying organic matter contained therein, being a direct incentive to cholera. If to such waters the precipitant be applied, they can be rendered as perfectly salubrious as water taken from the deepest wells. The same effect can be produced by the precipitant on tainted well-water, and the waters of stagnant ponds which are left for the use of cattle in the corners of fields.

For testing the superior salubrity of water which had been purified with the precipitant over the same water which had not been so purified, various experiments were detailed.

On the Oxidizing Action of Carbon. By Dr. CRACE-CALVERT, F.R.S.

On Disinfection. By WILLIAM CROOKES, F.R.S.

As an illustration of the want of general knowledge of the laws of disinfection, and the evils resulting from the absence of combined action between the local selfgoverning authorities, I may refer to what is being done in London in reference to the present outbreak of cholera. The drainage of one thousand acres, saturated with a powerfully oxidizing disinfectant, mingles in the sewers with the drainage from another thousand acres, to which a powerfully deoxidizing agent has been liberally applied, the result being that an enormous amount of money is expended on various disinfectants and deodorizers, with very inadequate results; and many valuable agents may ultimately fall into discredit from the want of a few simple discriminating rules for their proper application. Disinfecting agents of great value are being used for purposes for which they are totally unfit; useful but incompatible disinfectants are recommended in the same paper of instructions; and chemicals of the most potent description are given to ignorant persons without a word of warning as to how they are to be applied.

Disinfection is by no means so simple a process as is generally supposed. Chemists are aware that we cannot use one substance with equal efficacy in all imaginable cases. The process is one depending upon complicated chemical and physiological actions; and chemistry has placed at our disposal several substances which are applicable to various requirements of the case; but to pin one's faith to one agent only, be it carbolic acid, chloride of lime, Condy's fluid, or McDougall's powder, is to limit one's powers of disinfection in a very unwise degree; whilst to recommend all these things without discriminating in what cases they are severally to be used, is like sending a sick man to a druggist's shop, telling him neither what special drug to take, nor how much for a dose.

It is highly important that the best plan of disinfection adapted to the present, or like emergencies, should be definitely settled by some competent authority, and its adoption then made uniform throughout the country. The various disinfectants ought always to supplement each other, so that when the contents of the adjacent sewers blend together, the purifying action of the disinfectants used should pervade

the mass.

The word "disinfectant," in its ordinary sense, implies a body which will destroy an animal poison or virus, in whatever way it is accomplished; in a more restricted sense, the term is used to indicate an agent which destroys organic or offensive matter by oxidation or analogous action; whilst under the term "antiseptics" are classed those agents which arrest poisonous action by destroying the tendency to putrefy, and stopping chemical change.

Oxidizing disinfectants-those which actually burn up organic matter by means of combined or atmospheric oxygen-are by far the best known and most used; inasmuch as they appeal directly to popular prejudice, by destroying the foul odours which are the usual accompaniments of infection, whilst "antiseptics" have little or no action on these gases. This fallacious mode of estimating their relative value is one which does great injustice to antiseptics.

In the search for disinfectants suitable to arrest the progress of a zymotic disease, it is necessary to strike off at once a whole class of valuable agents which will not meet the requrements of the case. It is more than probable that the infectious matter partakes of the physical properties of a vapour or of fine dust; and it is consequently hopeless to attempt to combat the virus by non-volatile disinfectants. For this reason, charcoal, chloride of zinc, the permanganates, solutions of metallic salts, and other similar substances are of limited use: what is wanted for general purposes, is a liquid and a volatile disinfectant, which, after first acting on infected surfaces, will, by gaseous diffusion, pervade the infected atmosphere, and destroy the floating virus.

At first sight the action of a powerful oxidizing-disinfectant, like chloride of lime, or Condy's fluid, upon noxious vapours or even septic germs, appears perfect. In presence of an excess of either of these agents, all organic impurity is at once burnt up, and reduced to its simplest combinations; and could we always rely upon the presence of a sufficient amount of either of these bodies, no other purifiers would be needed. But in practical work, these disinfectants are always very inadequate, except for a short time after their application; at other times, the oxidizing agent has presented to it far more noxious material than it can by any possibility conquer; and being governed in its combinations by definite laws of chemical affinity, the sulphuretted and carburetted hydrogen, the nitrogen- and phosphorus-bases, and other vapours of putrefaction, will all have to be burnt up before the oxidizing agent can touch the germs of infection; whilst the continued renewal of the gases of putrefaction will constantly shield the infectious matter from destruction.

This is the chief objection to disinfectants which act by oxidation. If we arrange in a series the possible substances which may be present in an infected neighbourhood, and gradually mix with them chlorine or a permanganate, we find that these vapours, which have strong and fœtid odours, and which we will place at the commencement of the list, are the first to go; whilst the actual virus of the disease the organized particles which have little or no odour-are the last to be attacked. It so happens that the stinking gases of decomposition are of comparatively little danger, whilst the deadly virus-cells of infectious diseases are inappreciable to the sense of smell. Again, oxidizing disinfectants possess little or no permanent action. What they attack is destroyed perfectly, but what they leave has no special resistance to decomposition conferred upon it. They remove the products of decomposition, but they do not take away the power of subsequent decomposition. Mere deodorization therefore is no protection whatever.

Oxidizing disinfectants produce their effect by the actual destruction of the infecting substance. Antiseptics act by destroying its activity. The former act more energetically upon dead than upon living organic matter. Antiseptics attack first the opposite end of the list, and commence by destroying vitality. They exert little or no action on the foul-smelling but comparatively harmless gases of decom

position, whilst they act with intense energy on the inodorous germs of infection which these gases may carry into the atmosphere along with them.

If, therefore, the matter which conveys infection from one person to another be of the nature of an organized germ, if its tremendous powers of destruction are due to its vitality, then antiseptics are the only agents fitted to deal with these special cases; for whilst they leave almost untouched the majority of simply odorous gases, they seek out and destroy the one thing to be feared.

Now, of all antiseptics, those known as the tar acids, are the most powerful; and of these, commercial carbolic acid may be regarded as the representative. The powerful action which carbolic acid exerts on the phenomena of life, is the most remarkable property which it possesses. It may be looked upon as the test proper for distinguishing vital from purely physical phenomena; and in most cases its action is characterized by the certainty and definiteness of a chemical reagent. In the presence of carbolic acid the development of embryonic life is wellnigh impossible; and before its powerful influence all minute forms of animal existence inevitably perish. The vapour of carbolic acid in the atmosphere exerts a specially selective power on all minute organisms possessing life. If the infectious matter of cholera is possessed of organic vitality, as is now almost universally admitted, it will be destroyed beyond the possibility of revival, when brought in contact with this vapour.

Although the properties of carbolic acid are so valuable, the error I have already alluded to must be avoided, of considering it applicable to every case where disinfection is requred. Whilst its peculiar properties render it of wide applicability, it may on many occasions advantageously be replaced by other disinfectants. Thus, for purifying water for drinking or culinary purposes, it is far inferior to ebullition in the presence of Condy's fluid, which acts in this respect perfectly. Again, the liquid nature of carbolic acid renders it not so appropriate as McDougall's or Calvert's powder for many purposes, an excess of liquid being frequently a disadvantage where large quantities of solid offensive matter have to be dealt with, in which case either of the powders above mentioned is more suitable than carbolic acid.

Although much more expensive than carbolic acid for equal amounts of purifying work, chloride of lime also is a more appropriate agent where mere deodorization is the chief desideratum.

It has been assumed, I think on insufficient grounds, that the mere addition of permanganate of potash to drinking-water will certainly destroy the cholera virus. The oxidizing powers of this agent, although very energetic on dead organic matter, are successfully resisted by living organisms. Animalcules will live without apparent inconvenience for some time in water tinted with permanganate; and, assuming that the cholera poison possesses organic vitality, we have no guarantee that the agent in question will effect its destruction. For this reason, I should be inclined to prefer boiling the water after adding permanganate.

Let me here state a fact which ought to be generally known in respect to carbolic acid. For disinfecting purposes, as ordinarily applied, it is very extravagant to use it in the undiluted form. Except in special cases, the aqueous solution of the acid should invariably be used. Water will dissolve about 4 per cent., and for most purposes this solution is a better disinfectant than the undiluted acid. A small insect which is killed in a few seconds by immersion in the 4 per cent. aqueous solution, will live for a minute or more when covered with the undiluted acid. When the aqueous solution is added to sewage, the latter is at once disinfected; but on adding to a similar quantity of liquid far more than the corresponding amount of undiluted acid, this sinks, as a heavy oil, to the bottom, where it remains; and unless the mixture be well shaken, so as to bring the oil in contact with every portion, complete disinfection will not be effected for some time. To throw undiluted carbolic acid down the drains, as is done in many places at the present time, is simply to throw money away.

Allow me, in conclusion, to draw attention to the great importance of the scientific prosecution, by qualified persons, of accurate experiments and observations in reference to the cholera, similar to those undertaken in respect to the Cattle Plague. The third report of the Cattle-Plague Commission has given us more insight into that pestilence than we possess of any human zymotic disease; and there is no