426 EVENING DISCOURSES 
meat. ‘ Bloom,’ like beauty, is but skin deep, but it is not less highly 
valued. Loss of ‘ bloom,’ though without any nutritive significance, may, 
for instance, reduce the wholesale price of frozen lamb by as much as 3d. 
per lb. ‘Bloom’ is found to depend on two things: first, an adequate 
supply of the red pigment of blood and muscle, hemoglobin, and secondly, 
the translucency of the layer of superficial connective tissue and fat through 
which this pigment is seen. ‘ Bloom’ will therefore be impaired if either 
of these two conditions is below standard. Let us first consider the layer 
of connective tissue and fat. If its normal translucency is to be retained, 
absorption of water must be avoided, and so must excessive drying. In 
storage, absorption of water may readily take place when the cold carcass 
is exposed to a warm, humid atmosphere from which moisture may be de- 
posited on it. Turning to the second factor, the red pigment, hemoglobin, 
the intensity of the colour depends both on the concentration of the pigment 
and on the depth of the layer of muscle from which the light is reflected. 
Up to a certain point drying increases the colour by increasing both the 
concentration of the pigment and the translucency of the tissue, but if drying 
is allowed to persist beyond a certain point, it results in the formation of 
minute air-pockets, which, like a lot of minute air-globules in a piece of 
glass, scatter the light falling upon them and decrease the depth of the 
reflecting layer. At times this takes place to such an extent that the 
muscle appears a greyish yellow colour instead of red. Further, when the 
meat is exposed to air, oxidation takes place and changes the red hemo- 
globin into the dirty brown methemoglobin, but the rate at which the 
oxidation takes place depends on the pressure of oxygen, being greatest in 
comparatively low pressures. Moreover, decrease in the hydrogen-ion 
concentration also increases the rate at which methemoglobin is formed. 
Now, if carbon dioxide is added to the air of a beef store, both the hydrogen- 
ion concentration and the pressure of oxygen will be lower in the stored 
meat than if it was stored in air alone. High concentrations of carbon 
dioxide therefore produce rapid discoloration, but, fortunately, for concentra- 
tions up to 20 per cent. the increase in the rate of formation of methemo- 
globin is negligible. It is clear, however, that such high concentrations of 
carbon dioxide as to inhibit completely the growth of micro-organisms are 
not admissible. 
Application —What about application? Thestory I have told you of carbon 
dioxide results in the main from experiments carried out in the laboratories 
of the Low Temperature Research Station at Cambridge under Sir William 
Hardy’s direction. It appears clear that beef, with the aid of refrigeration 
plus the aid of carbon dioxide, can be maintained in first-rate condition, 
although only chilled, sufficiently long to carry it for 13,000 miles—that 
is, from one side of the world to the other. And to-day this is being 
done. The laboratory experiments have been fully verified by large-scale 
experiments at sea, and the historic shipments of meat under refrigeration — 
in the nineteenth century had their counterpart last year when a shipment 
of beef was made from New Zealand in the Port Fairy of the Commonwealth 
and Dominion Line. It was the first consignment of chilled beef to be 
carried overseas in gas-storage. It was strikingly successful, and similar 
shipments of chilled beef, though at present small, are now regularly made 
from Australia and New Zealand, while arrangements for the rapid develop- 
ment of the trade are being made by the great meat interests and the shipping 
companies. In the journal ‘ Food’ for July last a description is given of 
the twin-screw motor ship Port Chalmers, owned by the Commonwealth 
and Dominion Line, the first vessel to be specially built with gas-tight 
compariments suitable for the gas-storage of chilled beef. This vessel left 
a 
