In a paper on “The Spread of Bacterial Infection” (Journal of Hygiene, xix. No. 4, March 22, 1921) Dr W. W. C. Topley has shown the results of many months' observation of the progress of an epidemic in a population of mice. The author thus describes the experiment: “This experiment lasted from May 21, 1919, until June 11, 1920.…The epidemic started about the middle of October, 1919, and continued in the manner to be described until the conclusion of the experiment.…The period May 21 to September 17 is omitted.…During this time there was no indication of the active spread of infection.…The whole experiment may be divided roughly into four periods. The first extends from May 21 to Sept. 17, and has been referred to already. From Sept. 18 and onwards, only normal mice were added to the cage. From this date until Jan. 5, 1920, the mice were added in such a way as to keep the total number in the cage roughly constant. From Jan. 6 to April 27, 1920, three normal mice were added each day, except on two occasions when none was added. The number of mice in the cage during this period varied from day to day, reaching a maximum immediately before each considerable wave of mortality, and falling to a minimum just before its cessation. During the final period from April 28 to June 11, 1920, two normal mice were added daily instead of three.”

During the past four years it has been part of our routine work to examine samples of ground waters from wells and springs in various portions of Ohio, and, in so doing, organisms have been obtained from time to time conforming to the tests usually given as differentiating faecal bacteria.

Test baiting has shown that rats underground are distributed in a series of discrete colonies, each one in close association with a group of men. Interplay between colonies is rare in large mines although evident in small ones. In the absence of stables the rats must depend almost entirely on miners’ food scraps.

These observations were made during work carried out under a research grant from Safety in Mines Research Establishment, Ministry of Power, and I am indebted to the Ministry for permission to publish the results. I should like also to express my gratitude to Dr E. T. B. Francis who supervised the work, Mr. C. S. W. Grice of the Ministry of Power and Miss B. B. Jones of the Ministry of Agriculture, Fisheries and Food for their help in various aspects of the work.

1. Evidence is given that in recently inoculated persons the Widal reaction, even when serial quantitative tests are done, has no practical value in the diagnosis of enteric fever. Conscription enlarges permanently the inoculated proportion of the whole population.

2. The diagnostic value of any particular titre depends not only on the relative frequencies with which this titre occurs in normal and infected individuals but also on the incidence of enteric fever in the population and on the fashionableness of the Widal test as a diagnostic aid.

3. It is emphasized that blood culture is a more reliable aid to diagnosis than the Widal test.

The results obtained show:

1. The limits of precipitation of Felton antibody with solid ammonium sulphate in several sera; the effect on these limits of the addition of purified Felton antibody and the removal of tricresol from the serum.

2. That within these limits of precipitation small fractions can be obtained which differ from each other in their ratio of antibody to protein.

3. That the purity of such fractions throughout a given serum may be reduced by the addition of purified Pneumococcus antibody to the serum, and apparently increased by the addition of tricresol.

4. That the distribution of antibody in serum taken at intervals from a horse during immunisation changes progressively.

5. Differences in the distribution of the two antibodies in serum from a horse immunised to both Pneumococcus type I and diphtheria toxin.

Pen and field trials were conducted to assess the performance of the acute rodenticide pyriminil against the house mouse (Mus musculus L.). Four types of poison treatment were carried out using penned family groups of warfarin-resistant mice supplied with alternative plain foods. In each treatment pyriminil was included at 2% in a wholemeal flour/pinhead oatmeal/corn oil bait. Mortality was highest (46/54; 85·2%) when poison bait was offered for 4 days following 3 days of pre-baiting The same pre-baiting and poisoning technique was adopted in five field trials carried out against mice infesting farm building The efficacy of each poison treatment was estimated from the results of pre- and post-treatment census baitings; treatment success ranged between 53·7% and 96·7%, mean 80·5% It is concluded that pyriminil treatments are best carried out after a period of pre-baiting and that when pyriminil is used in this manner it is about as effective as zinc phosphide for the control of mice

Pp. 474–485. Messrs W. Martindale inform us that the Lactic Acid Pessaries reported upon by Dr John R. Baker in the Journal of Hygiene, Vol. 34, pp. 474–485, are not recommended by them as a contraceptive. They are made to the order of a clinic. (Editor.)

P. 528, line 26, for “glucose media, and did not affect saccharose and maltose media” read “glucose and maltose media, and did not affect saccharose media”

Strains of Corynebacterium diphtheriae isolated from a small outbreak in the restricted environment of a Mental Hospital were examined. All belonged to one serotype, but there was marked variation in diphthericin type, in sensitivity to bacteriophages and in the minor antigens possessed. One strain was non-virulent and laboratory-produced variants of this non-virulent strain showed changes in some of the characteristics used in the identification and typing of the organism, such as diphthericin type, sensitivity to bacteriophages and diphthericins, virulence, starch fermentation and, to a lesser extent, in antigenic structure. The epidemiological and experimental findings are consistent with the hypothesis that the strains isolated, both in the hospital and in the laboratory, were derivatives of a single parent and the mechanism of some of the variations could be related to changes in some structural component such as the cell membrane or the cell wall.

The general consideration of these results only tends to confirm the conclusions already arrived at. A uniform type of life evidently tends to a fairly uniform excretion of tissue cells from the udder. The case of Goat II also emphasises the effect of outside causes in increasing temporarily this excretion, while some of the samples of human milk show plainly that very high cell counts are not by any means necessarily connected with any diseased or disordered condition of the mammary gland.

We again emphasise the view we have already stated, viz. that in the cow the udder must be looked upon as an organ which has by breeding and selection been brought to an artificial condition of milk secretion and that this has been accompanied by a stimulation of the tissues to cell proliferation and that this proliferation may quite easily be caused to become abnormally great, leading to the appearance of an increased number of cells in the secretion. In support of this view we lay great stress on the fact constantly noticed by us, viz. that when the cell count is high for any reason, the cells themselves are always well-defined, showing little signs of degeneration, and also stain in a much more characteristic and definite manner, a fact which is diffcult to explain if they are to be considered to be blood elements.

Vaccinia virus inoculated on the chorio-allantois and causing infection spread to the uninoculated part of the membrane, the embryo, the allantoic and amniotic fluids and the yolk within 1 day.

The virus grew in the embryo and possibly in the uninoculated part of the chorio-allantois, but in the latter no macroscopic lesions were detected.

Virus increased in amount in the allantoic fluid and may have grown in the lining of the allantoic sac; it did not increase in the amniotic fluid; it was present in yolk and increased slightly but its local growth was doubtful.

The presence of haemagglutinin and complement-fixing antigen was related to the amount of virus.

Allantoic fluid from infected eggs could be a ready source of antigen for complement-fixation.

Both the sensitation of typhoid bacilli by serum and their ingestion by leucocytes when sensitised, have been shown by Ledingham (1912) to take place in accordance with the laws regulating an adsorption process, the removal of opsonin from a serum by bacteria, and of sensitised bacteria from an emulsion by leucocytes following very satisfactorily the adsorption equation y=kxn, where y= the amount adsorbed, x= the amount left free and k and n are constants.

The amount of clerical work involved, and the ramifications of the record system used, in an animal laboratory, are conditioned by the purpose for which the colony is maintained, and dependent upon how anxious its custodians are to control its size and guide its future. If, for instance, ease of operation and minimization of clerking is to be the overriding consideration one may secure a good supply of young rats by the simple process of allowing a flock of adult animals the freedom of a warm room containing bedding and food. One enters at intervals to clean and feed, and, eventually, to remove, for experimental work, those youngsters that look big enough to fend for themselves, taking care, at the same time, to leave a few of each sex to grow to maturity and guarantee the next generation. An occasional census of population and production is all that is necessary in the way of records.

Recently conflicting statements have been published in various countries on the prevalence and increased mortality from cancer, i.e. malignant disease in general. Statistics show a definite upward trend in the annual death rate from cancer, but opinions differ as to whether the increased mortality represents the actual increase in the incidence of the disease or is explained by such factors as the increased average age at death, improved methods of diagnosis and more careful records of the cause of death.