Dr Lucas discusses theories on why an all-meat diet is able to cure scurvy, guessing that the value is in fresh or immediately frozen meat.
To the Editor of the Lancet
p913 "Sir, —In a foot-note to page 49G of his " Manual of Practical Hygiene,", fifth edition, (London, Churchill, 1878), Parkes says : —"For a good deal of evidence up to 1848, I beg to refer to a review I contributed on scurvy in the British and Foreign. Medico-Chirurgical Review in that year. The evidence since this period has added, I believe, little to our knowledge, except to show that the preservation and curative powers of fresh meat in large quantities, and especially raw meat (Kane's Arctic Expedition), will not only prevent, but will cure scurvy. Kane found the raw meat of the walrus a certain cure. For the most recent evidence and much valuable information, see the Report of the Admiralty Committee on the Scurvy which occurred in the Arctic Expedition of 1875-76 (Blue Hook, 1877)."
I think that the last sentence in the above is not Parkes' own, but that it must have been added by the editor in order to bring it up to the date of the issue of the current edition. The experience since then of the Arctic Expedition in the Eira coincides with these. I refer to that portion of the report where the author tells us that "our food consisted chiefly of bear and walrus meat, mixing some of the bear's blood with the soup when possible." And again: "I do not think that, spirits or lime-juice is much use as an antiscorbutic, for if you live on the flesh of the country, even, I believe, without vegetables, you will run very little risk of scurvy. There was not a sign of scurvy amongst us, not even an anaemic face," (Lancet, Aug. 26th.)
So that, as far as this question of fresh meat and raw meat and their prophylactic and curative properties are concerned, ample evidence will be found in other published literature to corroborate that of the Eira. But when you take up the question of the particular change which takes place in meat from its fresh to its stale condition, you will find a great deal of diversity and little harmony at opinion. Without taking up other authors on the subject, we stick to Parkes and compare his with Dr Ralfe's views on this point. Parkes thought "fresh, and especially raw meat, is also useful, and this is conjectured to be from its amount of lactic acid; but this is uncertain,"1 while on the other hand Dr. Ralfe repeats, as a probable explanation, too, of the reason of fresh meat being an anti-scorbutic, but that it is due to the absence of lactic acid. For, from well-known chemical facts he deduces the following: — "In hot climates meat has to be eaten so freshly killed that no lime is allowed for the development of the lactic acid : in arctic regions the freezing arrests its formation. The muscle plasma, therefore, remains alkaline. In Europe the meat is invariably hung, lactic acid is developed freely, and the muscle plasma is consequently acid. If, therefore, scurvy is, as I have endeavoured to show ("Inquiry into the General Pathology of Scurvy"), due to diminished alkalinity of the blood, it can be easily understood that meat may be antiscorbutic when fresh killed, or frozen immediately after killing, but scorbutic when these alkaline salts have been converted into acid ones by lactic acid decomposition. The view of the alkalinity of the blood coincides with Dr. Garrod's theory, which, however, appears to have as a sine qua turn the absence of a particular salt- namely, potash. I am inclined to think that, taking into account the nervous symptoms which are not infrequently associated with a certain proportion of scorbutic cases, resulting probably from the changes taking place in the blood, not unlike those which occur in gout and rheumatism, there must be some material change produced in the sympathetic system. In many of the individuals tainted with scurvy there were slight and severe attacks of passing jaundice in the cases which occurred in Afghanistan. Can we possibly trace this icteric condition to this cause? This is but a conjecture so far. But there certainly is in Garrod's observations an important point which, if applicable to all countries, climates, and conditions of life, is sufficiently weighty to indicate the necessity for farther research in that direction, and that point is this : the scorbutic condition disappeared on the patient being given a few grains of potash, though kept strictly on precisely the same diet which produced scurvy.
—I am, Sir, yours truly, Ahmedabad, India, 30th Sept., 1882.
JOHN C. LUCAS."