The causes of death of the grouse are, of course, various. We ourselves have seen pleuropneumonia (in a bird long kept in captivity in Cambridge), pericarditis, necrotic patches in the liver, an obscure chronic disease of the peritoneum, and septic infection from a gangrenous fracture of the wing. On the other hand the great majority of birds, either picked up dead on the moor, or caught by keepers when weak and unable to fly, have been found to be all more or less in the same condition; they were wasted, badly infested with Trichostrongylus pergracilis, and often also with Davainea urogalli or Hymenolepis microps, or with both. More or less pathological change was seen in the caeca; the mucous membrane was often reddened, and under the binocular microscope considerable changes were seen, though we did not observe gross ulceration. Sections examined under the higher powers showed serious chronic inflammatory changes particularly in the immediate neighbourhood of the worms.

Up to the year 1906 tubercle bacilli were considered to occur in the faeces only in pulmonary or abdominal tuberculosis, due to ingestion of the infected sputum or to ulceration of the intestinal tract.

No hypothesis hitherto advanced with regard to the origin of Beri–Beri, has up till now found sufficient experimental confirmation to warrant its general acceptance. This applies especially to the conception of the disease as due to the presence of bacteriaor parasites in the blood, further to the infection theory as well as to the miasmatic theory1.

In a preliminary report (Hewlett, Villar and Revis, 1909, p. 278) published last year a summary of conclusions at which we had arrived with regard to the nature of the cellular elements present in milk was set forth. These conclusions were formulated on results obtained during a prolonged quantitative and qualitative examination of these cellular elements in milks obtained from known sources under veterinary supervision, and possess, we believe, a chronological significance which, with the exception of results published by Russell and Hoffmann (1907), has been somewhat lacking in many investigations. For this purpose we selected four dairy farms at which milk was being produced for sale on ordinary commercial lines, but under various conditions of environment, both architectural and sanitary. Together with these we were also enabled, through the kindness of Professor Percival, to make use of cows in the experimental herd of the University College of Reading.

(1) The premises of 50 manufacturers of ice-cream were inspected, their methods investigated, and bacteriological examinations made of samples taken

“a” immediately after heating,

“b” after cooling,

“c” after freezing.

(2) The trade is not carried on under the conditions or with the precautions necessary to secure a clean product.

The sources of the contamination of ice-cream.

(3) Bacteriologically polluted ice-cream is due to

(A) Insufficient initial heating;

(B) Contamination during cooling and freezing from

(a) unclean vessels and covers,

(b) the addition of unclean ice to hasten freezing,

(c) the unclean hands of the manufacturer,

(d) dirty surroundings.

The scientific method of the manufacture of ice-cream.

(4) To secure a pure ice-cream:

(a) All vessels should be thoroughly cleansed immediately before use and reserved for the manufacture of ice-cream. They should be stored in a clean place.

(b) The manufacturer's hands and forearms should be thoroughly scrubbed and cleansed before each stage of the process. The clothing likely to come in contact with the ice-cream should also be clean.

(c) Fresh milk should be used in its manufacture.

(d) The ingredients should be boiled directly over a fire for ten minutes, or heated by means of a water-bath at boiling point for 30 minutes. The latter method is the better as the former is liable to burn the mixture.

(e) The mixture should be frozen, immediately after boiling preferably in a freezer of the American pattern. Thereafter the ice-cream should be kept frozen while in the vendor's possession.

(f) No ice-cream should be exposed for sale 48 hours after boiling.

(g) The premises on which ice-cream is manufactured should be approved and registered by the local authority and should be constantly supervised.