The Graphic Method, which I first used in connection with the outbreak of milk-carried enteric fever which occurred in Clifton in 1897, is here applied to a similar outbreak of milk-carried scarlet fever.

In almost all investigations relating to ventilation of inhabited buildings determinations of the carbonic acid present in the air are essential. The method in common use is that of Pettenkofer, or some modification of it. This method has, however, the disadvantage that the determinations necessitate the carrying to and from the laboratory of large bottles, and take a considerable time. To overcome these drawbacks several methods capable of being conveniently applied on the spot have been devised, but their accuracy is hardly sufficient for practical purposes, hence they have not come into general use.

The following is an account of the bacteriological examinations for diphtheria bacilli made by me at the University Pathological Laboratory, from October 23, 1900 to Jan. 5, 1901; a period which includes all but the first week of the outbreak described in the preceding paper.

The outbreak of Diphtheria which occurred in Cambridge and Chesterton last October and November has already been the subject of a paper in this Journal, which dealt with the facts observed up to January 5th, 1901. The present communication deals with a return of the disease in the Spring of this year.

When fresh meat, or blood, is boiled the colour changes from the red of oxyhaemoglobin to a dull, brownish colour. The change of colour is due to splitting up of oxyhaemoglobin into coagulated proteid and haematin, which are precipitated. The dark colour of haematin, mixed with the white of coagulated proteid, gives the dull brown. When, however, meat has been salted, it has a characteristic red colour when cooked. It is evident, therefore, either that ordinary haematin is not split off from the oxyhaemoglobin, or that the colour of the haematin is masked by the presence of another pigment.

It will be accepted that milk containing large numbers of bacteria, as well as the products of their growth, is less suitable for food than unpolluted milk. A bacteriological examination of the milk in great cities generally will show that much of it in hot weather, and some of it at all seasons of the year, abounds in bacteria. Clinical experience also teaches that much of the milk in hot weather is unsuitable for food, especially for infants; because in them, owing to the rapidity with which the milk passes through the stomach, gastric digestion is almost no safeguard against the entrance of disturbing microorganisms into the intestines. Even pasteurization of milk charged with bacteria and their products does not restore it to its original condition, for the dead bodies of the bacteria and their toxins still remain. The changes in milk which are most deleterious being now known to be due to bacteria, it is theoretically conceded by all, that commercial cow's milk, the substitute for maternal milk, should be as nearly free as practicable from bacteria.

The idea of having the means of applying the Anti-rabic treatment of Pasteur in Shanghai, China, had its origin in the marked incidence of rabies among the numerous dogs of the Shanghai district and the consequent large mortality from this disease. The local condition was the more marked because of the short incubation period observed in Shanghai both in the human subject and in the rabbit inoculated from the rabid dog, being seldom much over a month in man and rarely over two weeks in rabbits inoculated subdurally.

The opinion has recently been expressed1 that the poisonous action of ordinary coal-gas and carburetted water-gas is probably in part due to the “Illuminant” hydro-carbons, of which ethylene is the chief, and not simply to carbonic oxide. In consequence of the doubt existing on this point one of us was asked by the recent Departmental Committee of the Home Office on Water-Gas to investigate the matter, and the results of the experiments which we were then able to make appeared in the Committee's Report2. In the main series of observations the animal was placed in a respiration chamber through which a current of air was passing at a known rate. With the current, before it entered the chamber, a known percentage of coal-gas or carburetted water-gas was mixed. It was found that whether ordinary coal-gas or carburetted water-gas was used the symptoms observed were those of carbonic oxide poisoning, and corresponded exactly to the percentages of carbonic oxide present. We also found that Benzene, which is one of the “illuminants,” is present in proportions far too small to contribute to the toxic effects of coal-gas or carburetted water-gas. Finally, we endeavoured to investigate separately the action of ethylene. The ethylene we then used was prepared in the ordinary way from sulphuric acid and alcohol, and when about 10% of the gas was mixed with air and supplied to an animal very distinct toxic symptoms were produced.

The question of the presence or absence of micro-organisms in the normal organs of the body has occupied the attention of numerous observers; yet, despite the fact that its solution is not accompanied by any great difficulties, the results of experimentation have been strangely at variance. For instance, Meissner stated that no bacteria capable of development are present in the living tissues of the healthy animal, while Zweifel (1885) expressed the opposite opinion, namely, that human organs habitually contain germs, that these germs, however, are anaerobic in character, their capability of development being limited by the amount of oxygen present in the blood stream.

The larva about to turn into a pupa comes to rest, the thoracic region becomes swollen, and the pupa gradually issues through a dorsal slit in the larval cuticle, which is ultimately thrown off with all its exterior chitinous appendages as well as those parts of the spiracles etc. which are superfluous.

Whatever may be the final form of the theories of Ehrlich as to the constitution of the bacterial toxines and as to the essential nature of immunity there can be no doubt of the stimulus they have given and are likely to give to inquiries relating to these subjects. As the present paper is intended to give a preliminary account of some researches bearing on the reactions of certain toxines it may be useful to recall the main features of the theories in question so far as they relate to the toxines investigated.

There have not been wanting those who have alleged that isolation hospitals have failed to fulfil the object for which they were erected, inasmuch as scarlet fever has during the last few years been prevalent to an exceptional extent. Those who argue thus, are in favour of diminishing expenditure on the erection and maintenance of isolation hospitals, and consider that we must trust to “improved sanitation” for diminishing and possibly in the end annihilating infectious diseases.