2^6 



NATURE 



[May 24, 1917 



same reagents ; but until there shall have been time 

 for a careful inquiry into the organic jaroducts of these 

 two parts we can only warn the public against em- 

 ploying for food any part of the rhubarb except that 

 which experience shows to be harmless." 



The Garden (1872, vol. i., p. 197) contains an extract 

 from an American paper which shows that a woman 

 residing between Oneida and Durhamville, New York, 

 died from the effects of eating as greens the leaves of 

 rhubarb, or pie-plant as it is known in the United 

 States, her death taking place after three weeks of 

 sufTering. "The leaves are poisonous, and should 

 never be eaten," concludes the paper's announcement 

 of the fatality. 



Judging from published statements {Gardeners' 

 Chronicle, ser. 3, vol. xv., pp. 340, 353, 384, 400), 

 there was a revival of interest in the question of 

 eating rhubarb-leaves in 1899. One correspondent 

 wrote (p. 384) : — " Rhubarb-spinach has been for many 

 3ears a favourite dish with us"; but the Secretary 

 of the Massachusetts Horticultural Society com- 

 municated the following \warning (p. 400). — "The 

 Gardeners' Chronicle for May 27 is at hand this 

 morning and the note on ' Rhubarb-leaves as a Vege- 

 table ' prompts me to say to you that instances have 

 been known here where their use as ' greens ' has 

 caused fatal results owing to the excess of oxalic 

 acid. A horticultural friend told me many years ago 

 that he had raised many seedlings, some of which (I 

 assume that the usual part was cooked in the usual 

 way) caused vomiting as certainly as ipecacuanha." 



A curious case is reported in the Pharmaceutical 

 Journal (1901, vol. Ixvi., p. 639) as follows: — "At an 

 inquest held at Ashstead on Friday, May 3, concerning 

 the death of John Lintott (thirty-nine), a scaffolder, 

 it was stated that on the previous Monday deceased 

 complained of violent pains and a doctor prescribed 

 for him, having found that he v.-as suffering from a 

 gastric attack. After the doctor left the patient some 

 cooked rhubarb-'eaves were given to him as medicine, 

 it being stated that the leaves were used as a vegetable 

 in parts of Hampshire. The man died next day, and 

 the doctor expressed the opinion that death was due to 

 excessive vomiting, causing exhaustion, produced by 

 eating rhubarb-leaves. The coroner expressed surprise 

 at hearing that stewed rhubarb-leaves were used as a 

 medicine or as a vegetable. A verdict was returned 

 of ' Accidental death, caused by eating rhubarb- 

 leaves.'" 



In 191 1, vol. Ixxxvi., p. 8, the same journal contains 

 the following, extracted, from the British Medical 

 Journal of December 31, 1910 : — "The author [Dr. 

 W. E. Burton] mentions two cases of rhubarb- 

 poisoning to which he was called, the symptoms being 

 similar in each case, and refers to the death from the 

 use of rhubarb which was the subject of a coroner's 

 inquest at Catford some weeks sines. Rhubarb, 

 although rightly regarded as a wholesome food and 

 an excellent substitute for fruit, does not agree with 

 everyone. It is possible that the presence of oxalates 

 in the urine and the severe intestinal irritation indicate 

 oxalic acid as being one of the agents responsible for 

 the toxic action. Oxalic acid and oxalates, chrysophan, 

 chrysophanic acid, and phaoretin are all found in 

 rhubarb-root, and are of an irritating nature." 



In a discussion on rhubarb-wine (Gardeners' 

 Chronicle, 1853, p. 406), the observations of one writer 

 seem to have especial interest as a possible explana- 

 tion of the cause of the variable effects produced by 

 eating rhubarb : — " However good the wine made 

 from rhubarb may be, I take the liberty of advising 

 your readers not to drink it. It is well known that the 

 acidity of rhubarb-stalks is owing to the presence of 

 an acid salt — the binoxalate of potash — a combina- 

 NO. 2482, VOL. 99] 



tion of the poison oxalic acid and the alkali potash. 

 This salt does not exist in Sufficient quantity in the 

 rhubarb-stalks to produce its f)oisonous effects, and 

 the same may be said of the wine. But there is 

 another danger attending its use in the form of wine 

 which ought not to be overlooked. All hard water 

 contains lime, and when mixed with the juice of the 

 rhubarb-stalks the binoxalate of potash is decomposed 

 and an oxalate of lime is formed. Now this oxalate 

 of lime is the constituent principle of the mulberry 

 calculus, and there is a peculiar condition of the 

 human body known to medical men as the oxalic 

 diathesis, which depends upon the presence of this 

 oxalate of lime in the blood (I use the word blood for 

 obvious reasons). This oxalic diathesis has been proved 

 by Dr. Golding Bird to be much more common than 

 it was supposed before this gentleman brought the 

 microscope to assist him in his pathological researches. 

 Such being the case, it is obvious that any article of 

 common use which contains this oxalate of lime, or 

 even the oxalic acid or its salts, must be more or less 

 injurious to health, more particularly to those in whom 

 there exists a predisposition to assume the oxalic 

 diathesis. It must be borne in mind that oxalic acid 

 is formed in the human body by the decomposition of 

 sugar, urea, etc., and the diathesis is not uncommon 

 from this cause. If it is thus easily produced in- 

 directly, a fortiori it is still more likely to arise from 

 the direct means of rhubarb-wine. Therefore I say 

 to your readers, eschew the doubtless very agreeable 

 beverage which has entered, through the medium of 

 your columns, into competition with genuine ' Sillery 

 mousseaux. '" 



The eminent physician and chemist. Dr. William 

 Prout, F.R.S. (1785-1850), regarded rhubarb as likely 

 to be a dangerous food owing to the large amount of 

 oxalic acid present in the leaf-stalks. Having anal3'sed 

 wine made from the stalks, he considered it a most 

 pernicious drink, and that its frequent use was likely 

 to produce stone in the bladder. He expressed the 

 opinion that an Act of Parliament ought to be passed, 

 if necessar}', to prevent the sale of so dangerous a 

 poison (Gardeners' Chronicle, 1853, p. 438). 



There is possibly something in the suggestion that 

 the chemical composition of rhubarb varies to some 

 extent according to the variety and also according 

 to the soil on which it is grown. A writer in the 

 Gardeners' Chronicle (1853, p. 357) stated that the 

 amount of water present was less when the plants 

 were grown on poorer soil, while the ^cid principle 

 was more abundant. 



Mr. Edward Solly, F.R.S. , published in the Trans- 

 actions of the Horticultural Society of London, ser. 2, 

 vol. iii., 1848, pp. 35-92, the results of his experiments 

 on the inorganic constituents of plants. Among the 

 numerous plants on which he experimented were 

 several rhubarbs. In the case of each of these he 

 gives the respective amounts of water, organic matter, 

 and inorganic matter found both in leaves and leaf- 

 stalks. In every case, as he shows by figures, there 

 was considerably less water present in the leaves than 

 in the leaf-stalks, but in most cases almost double, 

 in a few more than double, the amount, always very 

 considerably more, of organic and inorganic matter 

 was present in the former. It is therefore natural to 

 assume from the results of his investigations that 

 oxalic acid, or whatever is deleterious in the rhubarb- 

 plant, is present in greater proportions in the leaf- 

 blade than in the leaf-stalk. 



It mav be left to the discretion of those who chance 

 to read this article to decide whether or not it is advis- 

 able to eat cooked rhubarb-leaves or rhubarb in any 

 form. For at le^st a century the consumption every 

 vear of the leaf-stalks as a substitute for fruit has 



