Nickel carbonyl poisoning is a particular instance of nickel poisoning.

The lethal dose of nickel varies according to the method of application. When applied by subcutaneous injection, the physical condition of the compound influences the rate of absorption and therefore relatively large quantities may be required. In rabbits, the lethal dose is about 7½ mgrs. per kilogram body weight under the most favourable conditions when applied subcutaneously. In cats it is about 12½ mgrs. per kilogram body weight. When applied intraperitoneally, the absorbing surface is considerably larger and consequently the dose required to kill is smaller. In rabbits it is less than 7 mgrs. When applied in the form of nickel carbonyl vapour one meets with the most favourable conditions for rapid absorption and the dose is therefore still smaller. Rabbits die after the absorption of between 3 and 4 mgrs., while cats die after absorbing about 8½ mgrs. per kilogram body weight.

In the lungs, nickel carbonyl is dissociated and a nickel compound, probably the hydrated sub-carbonate, is deposited on the respiratory surface.

The nickel is dissolved from the respiratory surface by the tissue fluids and is then taken up by the blood.

Some of the nickel finds its way directly through the lymphatic channels into the bronchial glands.

In the dissolved condition, the nickel enters into complex combination with some constituent of the body.

The nickel is carried by the blood to the tissues, but a selective absorption is exercised by the brain and adrenals. In the case of other forms of nickel poisoning, the lungs also exert this specific selection. The nickel only stays for a short time in these organs.

The specific pathological changes which are produced by nickel in these organs are primarily a degeneration of the endothelial cells of the capillary vessels. It is possible that some further primary action is exercised on the ganglion cells in the brain and on the parenchyma cells of the adrenals.

The haemorrhages follow as the result of the fatty degeneration of the vessel walls and secondary changes result from the effects of the haemorrhages.

The nickel is excreted by the kidneys and intestines.

The method of poisoning with iron carbonyl is similar to that of nickel poisoning, but the amount necessary to kill in the former case is larger.

Iron carbonyl poisoning like nickel carbonyl poisoning is merely a specific instance of metallic poisoning.

Iron acts in a similar manner to nickel on the walls of capillary vessels, but no evidence of selection by any special tissues was obtained.

Cobalt has a toxicological action which is identical to that of nickel. The lethal dose however is higher than that of nickel and lower than that of iron.

After the inhalation of a quantity of nickel or iron carbonyl which is greater than the minimum required to kill, no form of treatment was found to avert death.

It is with much pleasure that I again express my gratitude to Dr Ludwig Mond, F.R.S., for having rendered this investigation possible, by defraying all the expenses, and by giving me the benefit of his advice.

I further desire cordially to thank Dr C. J. Martin, F.R.S., and the other members of the Staff of the Lister Institute, who have at all times been ready and willing to assist me. The work has necessitated incursions into several branches of science, and has required the acquisition of a variety of methods. I have made free use of their kind collegiality and am glad to avail myself of this opportunity of recording my indebtedness.

The literature of the subject has been given in Part I, q.v.

1. B. dysenteriae of Flexner has been found in the stools of 17 out 19 cases of asylum dysentery; no evidence of the presence of the Shiga type was obtained.

2. In 18 cases examined one week to 14 months after an attack of dysentery, B. dysenteriae was found only once (3 weeks).

3. No evidence has been obtained of the presence of B. dysenteriae the faeces of ward contacts (26 cases) with either normal or diarrhoeic stools.

4. The fermentative reactions of B. dysenteriae of Flexner towards maltose and cane-sugar are variable.

In this Journal (vol. VII. p. 501) Mr J. A. Craw has recently published a very sharp criticism of my calculations based on experiments by Madsen and Walbum regarding the so-called Danysz Effect.

(1) All fleas and bugs which have sucked the blood of animals dying from plague contain plague1 microbes.

(2) Fleas and bugs which have sucked the blood of animals which are suffering from plague only contain plague microbes when the bites have been inflicted from 12 to 26 hours before the death of the animals, that is, during that period of their illness when their blood contains plague bacilli.

(3) The vitality and virulence of the plague microbes are preserved in these insects.

(4) Plague bacilli may be found in fleas from four to six days after they have sucked the blood of an animal dying with plague. In bugs, not previously starved or starved only for a short time (one to seven days), the plague microbes disappear on the third day; in those that have been starved for 4 to 4½ months, after eight or nine days.

(5) The numbers of plague microbes in the infected fleas and bugs increase during the first few days.

(6) The faeces of infected fleas and bugs contain virulent plague microbes as long as they persist in the alimentary canal of these insects.

(7) Animals could not be infected by the bites of fleas and bugs which had been infected by animals whose own infection had been occasioned by a culture of small virulence, notwithstanding the fact that the insects may be found to contain abundant plague microbes.

(8) Fleas and bugs that have fed upon animals which have been infected by cultures of high virulence convey infection by means of bites, and the more certainly so the more virulent the culture with which the first animal was inoculated.

(9) The local inflammatory reaction in animals which have died from plague occasioned by the bites of infected insects is either very slight or absent. In the latter case it is only by the situation of the primary bubo that one can approximately identify the area through which the plague infection entered the organism.

(10) Infected fleas communicate the disease to healthy animals for three days after infection. Infected bugs have the power of doing so for five days.

(11) It was not found possible for more than two animals to be infected by the bites of the same bugs.

(12) The crushing of infected bugs in situ during the process of biting, occasioned in the majority of cases the infection of the healthy animal with plague.

(13) The injury to the skin occasioned by the bite of bugs or fleas offers a channel through which plague microbes can easily enter the body and occasion death from plague.

(14) Crushed infected bugs and fleas and their faeces, like other plague material, can infect through the small punctures of the skin caused by the bites of bugs and fleas, but only for a short time after the infliction of these bites.

(15) In the case of linen and other fabrics soiled by crushing infected fleas and bugs on them, or by the faeces of these insects, the plague microbes can under favourable conditions remain alive and virulent during more than five months.

(16) Chemical disinfectants do not in the ordinary course of application kill plague microbes in infected fleas and bugs.

(17) The rat flea Typhlopsylla musculi does not bite human beings.

(18) Human fleas do bite rats.

(19) Fleas found on dogs and cats bite both human beings and rats.

(20) Human fleas and fleas found on cats and dogs can live on rats as casual parasites, and therefore can under certain conditions play a part in the transmission of plague from rats to human beings, and vice versa.

All seven series give answers in the same sense, and we may conclude that we have definite experimental evidence that fatness increases the susceptibility to death from caisson disease. The regularity of the results in the guinea-pig experiments suggests that fatness is here the predominant influence in individual susceptibility. The difference in weight between the “survived” and ‘died” is not always in the same sense, and is in no case very large. The weight factor may therefore be relatively excluded in considering these results : indirectly it is of influence in that rats, like men, tend to become fatter as they grow older. Our results show pretty clearly that females are fatter than males, and, in the guinea-pig series, much more susceptible. Femality, like age, is not a quality which can per se have any influence on susceptibility. The increased susceptibility of females is probably simply due to their increased fatness, which tends to further increase during pregnancy. With regard to symptoms other than death our evidence is very meagre. Some symptoms, e.g. bends, may be presumed to be independent of fatness.

In a report on plague in Hongkong submitted to the Secretary of State for the Colonies in December 1902, Professor Simpson 2 says (p. 8) “The experiments undertaken demonstrate that pigs, calves, buffaloes, sheep, hens, ducks, geese, turkeys and pigeons are, in addition to rats, susceptible to plague, and particularly so when fed with plague material.” He points out that these experiments have a twofold importance for the Health Officer, viz.

1. Eighteen persons after eating a certain batch of pork-cheese, or vegetables infected from it, suffered from severe illness and three died.

2. The illness was caused by a Gaertner bacillus of the Aertrycke sub-group isolated from one of the fatal cases.

3. This bacillus was contained in the meat used for the pork-cheeses (brawn), infection being antecedent to preparation.

4. Part of the meat was obtained from a pig suffering from local injury or disease of one leg and the bacilli were no doubt etiologically connected with this condition.

5. The outbreak points to the need for a more complete and thorough veterinary inspection of meat before sale, and of the necessity for extended investigation into the diseases of animals used for human food caused by Gaertner bacilli.

The phenomenon of supersensitization observed on repeated injection of alien sera has lately aroused much experimental and clinical interest. The following cases which led me some three years ago, on clinical grounds to assume the occurrence of this phenomenon, appear worth recording, especially since the reaction happened not with anti-diptheritic or anti-plague but with anti-tuberculous serum.

The following general statements are applicable to the 50 cases of cerebrospinal fever which have been under notice here.

The total volume of serum given did not affect the frequency of abnormal reactions.

The total number of injections of serum, in certain cases, may have been a factor in inducding abnormal reactions.

The interval of time between the injections concerned was the primary influence in determining abnormal reactions.

It was not apparent that a preceding normal reaction predisposed to a subsequent abnormal reaction.

It was not apparent that a large administration of serum within the latent period predisposed to a subsequent abnormal reaction.

By means of a method introduced by one of us (Wilson, 1907), a bacillus closely resembling B. faecalis alkaligenes was recently isolated from Belfast tap water. This bacillus, for the purposes of this paper, will be spoken of as B. Grosvenor, it having been attained from a house in Grosvenor Road. We find that emulsions of this bacillus are agglutinated, often in high dilutions, by the blood serum from practically every case of the cerebro-spinal meningitis at present existing in epidemic form in Belfast.

In 1901 Miss Anderson (H.M. Principal Lady Inspector of Factories) and Dr Legge (H.M. Medical Inspector Factories) were instructed by H.M. Chief Inspector of Factories to investigate the conditions of labour in the Tinning of metals and metal articles with a view to the preparation of regulations for the conduct of this industry. Difficulties having arisen in assigning a cause for the plumbism undoubtedly existing among workers, and preparation of regulations appearing impossible without some knowledge of the source of illness, the writer was instructed to assist them experimentally in determining the causes.

Bile salt media have been in use since 1900, and during the seven years which have elapsed it has been shown that B. typhosus, B. enteritidis (Gaertner), B. coli communis and similar organisms grow on these media just as well as on any other nutrient media. At 37°C. the growth of most of the organisms of the air and soil is inhibited by bile salt media.

These media can therefore be used with confidence for the isolation of B. typhosus and other intestinal organisms.

In a previous paper (This Journal, vol. VI. p. 524) we have given an account of the quantitative estimation of plague bacilli in the blood of 16 septicaemic cases. It remains now to supplement this number with a further series and to add some observations on the infectivity of the urine and faeces.

1. Many horses immunised against other bacteria or bacterial products will give a large local reaction to mallein, but this is usually not associated with a rise in temperature. In the case of horses injected with diphtheria toxin, the size of the swelling appears to related to the degree of immunity attained. This point has not yet been established in the case of horses immunised against other bacterial products.

2. This local reaction disappears rapidly and can thus be distinguished from the reaction in the case of glandered horses.

3. In the few cases when a rise in temperature took place (3 cases out of 56) the curve was markedly different from that obtained in the case of glandered animals.

4. Other bacterial products react similarly to mallein upon immune horses.

The investigations described in the present paper were carried out in connection with the experimental plant laid down by the Corporation of Belfast with a view to discover the most suitable method of dealing with the sewage of that city. The necessity of some form of sewage purification arises in Belfast in connection with what is known as the “foreshore nuisance” in Belfast Lough.

(1) Morphologically and culturally the Bacillus pseudotuberculosis rodentium (Pfeiffer) bears a strong resemblance to B. pestis.

(2) The filtrate from an autolysed agar culture of B. pseudotuberculosis rodentium (Pfeiffer) and a similar filtrate from a B. pestis culture both gave a precipitin reaction with pest serum.

(3) It has been found possible to immunise both guinea-pigs and rats against plague by means of inoculations of cultures of B. pseudotuberculosis rodentium (Pfeiffer), and this immunity lasted in many cases at least six months.

1. The typhoid bacillus can survive in natural soil in large numbers for about 20 days and is still present in a living condition after 70 to 80 days.

2. There is no evidence that the typhoid bacillus is capable of multiplying and leading a saprophytic existence in ordinary soil.

3. In some samples of soil, but not in all, the typhoid bacillus dies out much more rapidly (in 11 days) if the soil has previously been subjected to sterilisation by steam under pressure. This is apparently due to the production of bactericidal substances during sterilisation.

In any method of standardisation it is necessary that the test shall be carried out at a constant temperature, as the disinfection process has a high temperature coefficient. For any method to be of general application, it is also necessary that the temperature selected shall be adhered to in all determinations, since the temperature coefficient of disinfection varies for different disinfectants. The temperature adopted was 20° C.

In the case of vegetative organisms a disinfectant varies in efficiency as much as ten times according to the organism against which it is tested. Some disinfectants are more efficient against one vegetative species of bacteria, others against another.

The presence of 10% blood serum reduces the efficiency of 1% phenol about 12%. The effect upon emulsified disinfectants is somewhat greater. With mercuric chloride the reduction was much greater, a 0·5% solution being reduced to from 0·6 to 0·06 of its original value as the concentration of serum was increased from 5 to 30%.

Fleas (Aphaniptera, Siphonaptera) are wingless insects which run or hop about. They are for the most part parasitic in their habits, being found only on the homoiothermic vertebrates, especially on those which build nests or have more or less fixed haunts or homes. Like the majority of other parasites they have the body flattened, but differ from most parasitic insects in that this flattening is in a lateral direction, so that the transverse diameter of the body is small and the vertical diameter great. Attention has already been drawn to certain other morphological peculiarities of these insects (vol. VII. p. 446).

We intend to give in this paper a short account of (1) the laws concerning the supply of drinking water to ships in some of the chief civilised countries of the world; (2) the results of bacteriological examination of the water on steamships; (3) the chief deficiencies in supply and storage which have come under our notice, and (4) the reforms which we consider urgently necessary.