All observers agree that Musca domestica comprises over 90 percent. of the flies found in houses; my own observations show 97 percent. M. domestica is most easily distinguished by the venation of its wings, the fourth vein being bent up at an angle, and by the four longitudinal black stripes on the thorax. It is thus easily distinguished from Homolomyia canicularis, another somewhat smaller fly which frequents houses and forms the bulk of the remaining 3—10 per cent.

A case recently tried before Mr Justice Warrington (The Flour Oxidising Co., Ld. v. J. and R. Hutchinson) has brought to light, what I do not imagine is a matter of common knowledge, namely that large quantities of flour both in this country and abroad are artificially bleached in order it would appear primarily to satisfy the fancy of the public for white bread. The popular taste for the appearance of their food naturally leads the caterers to satisfy it; the yellowness of milk and its richness are usually associated together in the mind of the man in the street consequently it is very difficult now-a-days to purchase milk which has not been artificially coloured.

The following experiments constitute an attempt to follow out in detail the stages by which immunity is established, in the course of a generalised bacterial infection (Pseudotuberculosis of rabbits). Two aspects of immunity are considered, firstly the presence, in the circulating fluids, of specific antibacterial substances, and secondly the power of rapidly producing such substances in answer to the specific stimulus. That is to say, attention is directed, not only to the quantity of specific antibodies present on any day of the disease, but also to the response which the animal can make to various doses of bacterial vaccine. For the immune animal is both more vigorous and more sensitive than the normal, in its reaction to a renewed dose of poison (Wassermann and Citron, 1905). Naturally the facts established with regard to one disease only, cannot be predicated at once of other diseases, in other animals. Still it is hoped that the systematic study of one disease may give some help in coordinating the large but somewhat disjointed mass of clinical observation which is already available.

It is generally conceded that there is no one circumstance associated with occupation which has a more baneful influence upon health than the protracted inhalation of dust.

During the year 1904, a year which included four months of hot summer weather, the mortality among infants under one year old in England and Wales was 145.3 per 1000 births. Of this mortality 21.8% died of diarrhoeal diseases and 31.5% from wasting diseases.

The species of organisms used were B. coli, B. typhosus and B. enteritidis Gaertner. With these organisms:

(1) When a fresh broth culture is made with a small inoculation there is a period during which there is no increase in the number of bacteria present.

(2) When this period is over the bacteria commence to divide regularly; this is shown by the fact that the logarithms of the numbers plotted against time are found to fall on a straight line. This regular growth persists until (or nearly until) a maximum has been reached, after which the numbers remain more or less constant and then slowly decline.

The time necessary for a complete division to take place (generation time) was determined for various temperatures between 20°C. and 42°C.

(3) The effect of temperatures between 20° and 35.3°C. upon the rate of multiplication is in accordance with the Arrhenius-Van 't Hoff law; above this temperature the effect diminishes.

The discovery of cobalt tetra-carbonyl by Dr Hirtz and Mr Cowapp in Dr Ludwig Mond's laboratories offered a further opportunity of studying the toxic action of volatile compounds of the heavy metals. Through the kindness of Dr Mond, a sufficient quantity of cobalt carbonyl was placed at my disposal for physiological experimentation.