During the period July 1st—October 31st, 1911, 15,332 rats were examined for plague infection. These rats were obtained (see Map facing p. 311) partly from the area which in the previous year had been found to be infected with rat-plague and partly from the districts immediately adjacent to this area.

As a result of the present enquiry 27 farms or other premises were found to harbour plague-infected rats.

These 27 places are all within the area previously pronounced to be infected. No plague-infected rats have been discovered outside this area.

Experience of rat collection during the present enquiry showed that the rat destruction which had been maintained by local enterprise since the end of 1910 had in many localities appreciably diminished the rat population.

On June 30th, 1911, we proceeded to Ipswich, with instructions from the Local Government Board to assist in an enquiry, the purpose of which was to determine the extent of the plague epizootic amongst rats in the surrounding districts. The share of this work allotted to us consisted in examination, at the Municipal Laboratory, of the animals received, and in selection, for further investigation by the Board's pathologists in London, of material which appeared suggestive of plague. For this purpose, rats presenting features in any degree consistent with the presence of plague were regarded by us as suspicious.

(1) Chickens fed on a 1/20th their body-weight daily of padi, cured or parboiled unpolished rice, or fresh (partly polished) rice, remain free from polyneuritis for at least 28 to 100 days.

(2) Chickens fed on the same ration of polished Siam rice develop symptoms of polyneuritis in from 20 to 70 days.

(3) When the polished rice is soaked in excess of water for 24 hours the birds succumb to polyneuritis in from 10 to 35 days; when the rice is soaked for 48 hours the disease appears still more readily, viz. in 15 days.

(4) Chickens fed on 1/20th their body-weight of parboiled rice which had been soaked for 24 hours also develop polyneuritis in from 13 to 39 days. This fact is of practical importance, as epidemics of beri-beri have been traced to the practice of soaking unpolished rice prior to cooking and discarding the water.

(5) Although birds fed on diets of polished rice, sago, or glucose develop polyneuritis, when fed on commercial starch they often fail to do so and merely lose considerably in weight. An explanation is offered.

(6) While fowls fed on 1/20th their body-weight of padi remain free from polyneuritis for at least 60 to 100 days, when this ration is supplemented by 1/6th the body-weight of washed unpolished rice or 1/10th of polished rice polyneuritis appears in from 20 to 30 days.

(7) On the other hand, chickens fed on rations varying from 1/5th to 1/30th of their body-weight of washed unpolished rice develop polyneuritis in about the same time, 10 to 20 days.

(8) On dietaries composed of rations of polished rice varying from 1/20th to 1/40th the body-weight and of yeast varying from 1/2500th to 1/3500th the body-weight pigeons and chickens do not develop polyneuritis until at least 32 to 100 days have elapsed, but when the carbohydrate ration is doubled by the addition of polished rice or sago the birds fall ill in from 13 to 46 days.

(9) Even when daily rations of polished rice as large as 1/10th the body-weight are fed to chickens together with varying amounts of yeast, 93 to 98 per cent, of the carbohydrate is digested and absorbed and the excreta contain no anti-neuritic substance. This shows that the rapid development of polyneuritis induced by feeding large rations of starch is not due to interference of undigested carbohydrate with the absorption of the active material.

(10) Intestinal bacteria, unlike yeast, contain little anti-neuritic substance.

1. Sera and antisera when kept in the dark at room temperature sealed in glass tubes occasionally give specific reactions after a period of 12 years. In most cases, however, negative results were obtained with the antisera, whilst in others the reactions were non-specific.

2. Fowl blood will still give specific complement fixation and precipitin reactions after being in the alimentary canal of either Argas persicus or Ornithodorus moubata for at least 23 months. The gut contents of Pediculus vestimenti fed on man three days previously, also will give specific reactions with human antisera.

The diagnosis of bubonic plague in rat cadavers, the examination of which is a recognised method of prophylaxis for ships or other communities, which may have been in contact with endemic centres, is attended by especial difficulties, and, on the other hand, calls for especial speed and finality in technique.

Several attempts have been made at various times to obtain a mathematical expression of the relation between dosage, body weight and death time. The subject has recently gained importance through the interesting publications of Dreyer and Walker, who have put forward such a formula, and have illustrated its application to toxicity determinations for a number of substances, and, in particular, for different samples of diphtheria toxin—a matter of considerable practical importance. I propose to examine the theoretical basis of their formula, and its relation to formulae which other workers have suggested, and to criticise the evidence with which they have illustrated its application to experimental material.

In order to determine whether non-lactose fermenting bacilli are numerous in fresh milk, a series of experiments was made in the early part of this year on samples of fresh dairy milk, taken in Dumfriesshire, for routine bacteriological examination. The samples were brought to the laboratory with the least possible delay, and in no case did more than seven or eight hours elapse between the time of milking and the inoculation of plates. In the majority of instances, the interval was much shorter.

In 1909, in a paper published from the Federated Malay States Institute for Medical Research, Fraser and Stanton in discussing the etiology of beri-beri found that polyneuritis could be produced in fowls by a diet of polished white rice and that the fowls remained healthy if, in addition to the polished rice, they received a sufficient quantity of rice polishings or a quantity of an alcoholic extract (evaporated at a temperature of 52° C.) of whole rice. They established the fact that the essential cause of beri-beri was to be sought for in a nutritive defect, and they endeavoured to determine by chemical methods precise differences between rices capable of causing polyneuritis in fowls and rices which did not cause the disease. Their experiments had shown conclusively that highly polished rice gave rise to the disease but whole rice did not and that the disease could be cured by adding rice polishings to the diet. The chemical examination showed that, whereas whole rice contains about 0·469 per cent, of phosphoric oxide, polished white rice contains only about 0·277 per cent, and the polishings contain about 4·2 per cent.

Owing to the difficulty of satisfactorily explaining many facts in serological work, there has been a tendency in the last few years to consider serological phenomena more and more from a physico-chemical point of view.