time cases arise which have a more or less malarious character; in such instances, the height of the ground water and the nature of the soil will have to be carefully investigated. Nor must it be lost sight of that there are cases on record which show that heaps of decaying or drying vegetable substances will cause intermittent fever; for instance, it is an accepted fact in the Netherlands, France, and Italy that the steeping of flax in stagnant water and spreading it out to dry has been followed by paludal fever. In India large masses of exhausted indigo plants put in heaps has caused intermittent fever, when in a state of putrefaction, to families to leeward of the heaps.

(364) Prevention of Malaria.

The preventive measures are good drainage, the removal of stagnant ponds, of decaying masses of vegetation or heaps of vegetable matter. Travellers having to pass through a malarious country may to a certain extent protect themselves from malaria by dosing with quinine; it has been repeatedly shown that provided the doses are large quinine has a real preventive quality. The doses of the sulphate should be 5 grains at first twice a day, and then gradually increased up to any dose which can be borne without singing in the ears or other symptoms of "quinism."

CHAPTER XXXII.

MICRO-PARASITIC MALADIES PRIMARILY ATTACKING THE

INTESTINE.

ENTERIC OR TYPHOID FEVER.

ENTERIC or typhoid fever is a malady produced by a microorganism which attacks the intestine in the first place, and afterwards other organs; it is attended with fever, and mostly diarrhoea, and other systems of constitutional disturbance.

(365) Statistics of Mortality from Enteric Fever.

The average deaths from enteric fever in England during the eighteen years from 1869 to 1886 inclusive reaches the mean number of 7,203, the extreme yearly numbers being 5,061 and 8,913; the mortality per million from typhoid fever is given for the same number of years in rates varying from a minimum of 173 to a maximum of 371.

Typhoid fever is especially a disease of the young adult, and is more prevalent in country places than in well-drained towns. Diffused generally throughout the civilized world it is particularly prevalent in warm climates such as India. It is the most fatal of all the diseases to which the British soldier in India is liable, and it occurs in all parts of India from the Eastern to the Western frontiers; on the hills and mountains as on the plains there is no station and cantonment which is exempt.1 This great prevalence in India is more due to sanitary than to climatic conditions.

1 Twenty-fourth Annual Rep. San. Com. India. 1887.

During the eight years ending 1887, the following are the admission and death-rates of the army in the three Presidencies.

(366) Case-Mortality of Enteric Fever.

The case-mortality of enteric fever in England is somewhat less now than formerly; during the three years 1886-8 the casemortality of the hospitals of the Asylum Board varied from 14:59 to 14.85 per cent. Murchison's statistics derived from the London Fever Hospital, 1848-1859, give an average of 17·2 per cent., and the average mortality of 28,051 cases treated at various hospitals at home and abroad in various years up to 1870 is given as 17:45 per cent.

The liability to attack is influenced enormously by age, but the death-rate is not influenced in anything like the same proportionin which it contrasts with typhus, for instance Murchison gives the following figures derived from London fever hospital experience:

From whence it appears that the death-rate increases with advancing age to much less extent than typhus.

(367) Incubation Period.

If the modern view is correct, viz., that typhoid depends upon the invasion of the intestine by a micro-organism, there ought not to be a very definite incubation period. For in experiments with anthrax (a micro-organism of something the same nature), in which the bacillus anthracis has been introduced into the system

of animals by dosing the natural food passages, the incubation period has been variable. For instance Koch, Gaffky and Loeffler 1 fed sheep, some with large doses of anthrax, others with small, the feeding being done in such a manner as to avoid all wounding of the mouth. In the first case in which sheep were fed with large doses, they died without exception in a few days from anthrax infection; on the other hand, out of ten sheep who daily took a small dose of anthrax, those that were affected at all died respectively the 5th, 6th, 11th and 19th day after the beginning of the feeding. In all the mortal cases a post-mortem examination made it clear that the anthrax had infected the intestine, the seat of infection being as in typhoid the lymph follicles and Peyer's patches.

After these experiments it will cause no surprise to find cases like those cited by Murchison in which it appears clear the incubative period was only two days. In most of the cases recorded the incubation period has been about two weeks, but it may be much shorter and it may be longer.

(368) Seasonal Prevalence.

Enteric fever is markedly influenced by season, by far the greater number of cases in Europe and America occurring in the autumn, hence one of its synonyms "autumnal fever"; the least number of cases occur in April and May.

5,988 cases admitted into the London Fever Hospitals during the twenty-three years from 1848 to 1870 were distributed throughout the months of the years as follows:

1 Mittheilungen aus dem Kaiserlichen Gesundheitsamte. Berlin, 1884.

The experience of the Metropolitan Asylums Board is very similar (see Chart opposite). In the fifteen years ending December, 1888, the maximum occurred eleven times in October, three times. in November, once in December, once in January; in 1880 the cases were few, and it was equally prevalent in August, September, and October, there being no marked difference in each of the three months, the curve being here continued, or to speak more accurately interrupted, by a straight line.

Buchan and Mitchell's curve1 of the mortality mapped out by Bloxam's method for the deaths in London during the thirty years, 1845-74, places the maximum in the last week of October, which would well coincide with hospital experience. They point out its great similarity with the scarlatina mortality curve, differing from it though in the duration and phases of the minimum period. "Scarlatina falls below its average in the beginning of January, typhoid fever not until the last week of February; scarlet fever has its absolute minimum period from the middle of March to the middle of May, typhoid fever from the middle of May to the end of June; scarlet fever begins steadily to rise in the second week of May, typhoid not until the beginning of July, when the heat of summer has fairly set in."

(369) Bacteriology of Enteric Fever.

Recklinghausen2 in 1871 found in a case of abscess of the kidney which had complicated typhoid, colonies of micrococci; he did not consider these a factor in the production of typhoid, but an accidental complication. In the following year Eberth also found micro-organisms in the corpses of typhoid cases.

3

In 1875 Klein found in a case of fatal typhoid, in the mucous membrane of the intestine, a fungus with copious mycelium and numerous macro and micro-gonidia; in a later communication Klein recognised micro-organisms in the spleen and noted the presence of micrococci in the mucous membrane of the intestine and the lymph follicles. Browicz, in 1875, discovered in the kidneys, the spleen, the muscular structure of the heart, and in the

1 Op. cit.

2 Verhandlung der physicalisch-medicin Gesellschaft in Wurzburg, 1871.
3 Zur Kenntniss der bacteritischen Mykosen. Leipzig, 1872.

4 Reports Medical Officer L. G. Board. 1875