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"On the adulteration of bread as a cause of rickets"

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(3 October 1857): 351-52

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To the Editor of the Lancet.

Sir,--Having, like many others, been out of town, I did not see the communication of Dr. Coley respecting bakers' bread, in the Lancet of August 22nd, until to-day. As he has very much mistaken my views, I shall be obliged if you will allow me briefly to reply. Dr. Coley speaks of what I have said in my former paper of July 4th as an "hypothesis which refers the origin of rickets to decomposition of the phosphate of lime in the bones, produced by the alum contained in the bread made by the London bakers." This is entirely wrong, as I attributed the great prevalence of rickets in London and many other places to the decomposition by alum of the phosphate of [351/352] lime of the wheat-flour, the children being thus deprived of that material which they require for the nourishment of the bones; and I quoted Baron Liebig as my authority for this chemical decomposition. Dr. Coley thinks that I consider nutrition too much of a chemical process, but if he supposes that the phosphate of lime of the bones can be formed from the phosphate of alumina and sulphate of lime contained in bakers' bread, his opinion of nutrition is much more strongly chemical than mine.

Dr. Coley says: "Dr. Snow's theory is without foundation, otherwise every child partaking of the bread made by London bakers would necessarily have rickets." If Dr. Coley had done me the favour of reading my paper before replying to it, he would have found that I have expressly stated that many children derive a sufficient quantity of phosphate of lime from milk, potatoes, and other articles of food independently of the bread, and therefore escape having rickets, although they eat bakers' bread, in which the phosphate of lime is usually destroyed. I also remarked that rickets might arise from derangement of the digestive and urinary functions.

Besides the necessity of referring to Dr. Coley's paper on account of the mistakes into which he has fallen respecting my statements, I have another and more agreeable reason for doing so, as he has unwittingly supplied a fact which very much confirms my views. Having alluded to the great prevalence of rickets amongst children in the towns of Belgium, he says: "This unhealthy condition of the osseous system in Belgian children is traceable to the generous use of vegetable soups, their almost entire deprivation of bread and animal food, bad nursing," etc. etc. The italics respecting the bread are Dr. Coley's, and show the importance he attaches to that particular. Now, the privation of bread must deprive the children of that portion of phosphate of lime which they ought to obtain from the bread as completely as if, eating the bread, the phosphate of lime were destroyed by alum; and, it is extremely improbable that vegetable soups contain enough of this salt for the supply of the growing bones. I do not wish to beg the question, or I might say that the prevalence of rickets proves that the soups do not contain enough phosphate of lime.

Dr. Coley alludes to the frequent concurrence of scrofula and rickets as proof of what he calls the constitutional origin of rickets; but admitting the applicability of this phrase in several cases, what is so likely to injure the constitution as a deficiency of one of the most important constituents of the body? Moreover, if the new views of Dr. Churchill be correct, and scrofula and consumption are caused by a deficiency of phosphorous in the body, the adulteration of bread may tend seriously to promote the prevalence of these maladies.

The observations I have been able to make on the presence or absence of rickets, in a late excursion into the provinces, entirely confirm me in the views stated above; but I regret that I have not yet had time or opportunity to collect evidence in that numerical form which would leave no room for doubt or cavil on the subject.

I am, Sir, your obedient servant,

John Snow, M.D.

Sackville-street, Sept. 24th, 1857.

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