July 8, 1875] 



NATURE 



197 



period the potato bore enormous crops of berries, whilst since 

 the prevalence of the murrain it has almost ceased flowering and 

 fruiting ; and in these facts (?) lies the whole gist of the matter. 

 The production of fruit in profusion is regarded as an exhausting 

 process so far as the tubers are concerned, and this is so far a 

 very philosophic assumption, inasmuch as fruit-bearing is one of 

 two ways to ensure the propagation of the plant. But here it 

 becomes necessary to give the author's view respecting the 

 "Functions of Nitrogenous Matter." It is in substance that 

 the formation of fruit draws the nitrogenous matter from the 

 plant and tubers, and when excessive crops of fruit are borne, 

 the tubers are left without sufficient of this vital principle to con. 

 tinue the existence of the plant. On the other hand, when little 

 or no fruit is produced, the tubers are left overcharged with this 

 nitrogenous matter, which here becomes a source of decomposi- 

 tion, in proof whereof we are gravely told that the decay of 

 manure is due to the presence of nitrogenous matter. It has 

 long been admitted that excessive luxuriance predisposes in 

 favour of disease ; but this assumed presence of nitrogenous 

 matter in the wrong place will hardly be accepted as an ade. 

 quate explanation of the phenomena presented by the curl and 

 the murrain. It is assumed that the potato left off bearing 

 berries just about the time of the appearance of the murrain, 

 and this we are told was brought about by the use of artificial 

 manures containing a large percentage of nitrogenous matter. 

 The " curl " was cured or rather prevented by using sets (tubers) 

 from plants which had not been allowed to ripen seed. We 

 have not space to examine the writer's arguments in support of 

 this theory, but we may give his remedy. 



" Having so fully set forth the natural habit of the plant, and 

 JO copiously elucidated the principles on which my theory of the 

 disease is founded, the means of its prevention all but suggest 

 themselves. They require compHance with but two simple 

 forms : regenerate through the seed two or three times, and 

 abstain as nearly as practicable, not only from nitrogenous arti- 

 ficial manures, such as guano, sulphate of ammonia, rape- cake, 

 nitrate of soda, but also from strong farmyard manure." 



We do not intend to attempt to refute the author in detail 

 here, as it would occupy too much space ; but we may observe 

 that the condition of practical experience imposed upon the 

 competitors for the Cathcart prize, of which our author com- 

 plains because it disqualified him, was the wisest provision in 

 the whole business. It is just this want of practical experience 

 and personal knowledge that has led him astray in regard to the 

 berry-producing power of varieties now cultivated, of the descrip- 

 tion of manure usually employed, &c. Why all varieties of the 

 potato in all parts of the kingdom should have become just so 

 much overcharged with nitrogenous matter at exactly the same 

 time as to take the disease is rather puzzling. Does the writer 

 not know that the Vine Mildew, Oidium Tuckeri, has been suc- 

 cessfully combated ? 



Since the preceding lines were written, the report of a new (?) 

 disease having attacked the potato-crop has caused some con- 

 sternation and alarm. First we hear that it has destroyed the 

 entire crop of American varieties in the trial gardens of the 

 Horticultural Society at Chiswick ; then the appearance of the 

 same disease is observed in Northumberland, but here again only 

 American varieties are affected, and a vain hope is indulged in 

 that it may soon be stamped out. The following week, how- 

 ever, the horticultural journals begin to team with letters from 

 the most distant parts, and the unwelcome truth that all varieties 

 are alike attacked, or liable to be attacked, is forced upon us.- 

 True, we read of certain varieties being diseased, whilst others 

 remain healthy in the same garden, but we fear there is no 

 ground for believing that it is restricted to any particular varie- 

 ties, whether of English or American origin. The Rev. M. J. 

 Berkeley is investigating the nature of the disease, which he 

 regards with considerable anxiety. It appears to be caused by, 

 or perhaps succeeded by, a fungus growth. At all events a 

 fungus is present ; but we must await r thorough microscopical 

 examination for more precise information. Mr. Shirley Ilibberd, 

 in a letter to the editor of the limes, takes a more hopeful view 

 of the matter than we can ; and his description of the nature and 

 spread of the disease is not borne out by the reports from other 

 quarters. His statement that the new disease begins in the " set" 

 and progresses upwards, is in direct contradiction to the expe- 

 rience of others. In the Gardemr's Chronicle it is affirmed that 

 the sets of affected plants were cut in two, and in no case was 

 there the slightest evidence of disease in the tuber causing imma- 

 ture and diseased haulm. Possibly, however, it may manifest 

 itself in different forms. 



SCIENTIFIC SERIALS 



The Journal of the Chemical Society, April and May. — The 

 April number contains the following papers : — Researches on the 

 paraffins existing in Pennsylvanian petroleum, by Thos. M. Mor- 

 gan. This paper is followed by some remarks on the same subject 

 by Prof. C. Schorlemmer. — On Groves' method of preparing chlo- 

 rides, by the same. — A note on aricine, by David Howard.— On 

 the precipitation of metals by zinc, by J. L. Davies. The au- 

 thor failed to precipitate to any large extent many of the metals 

 which, according to some metallurgical books, are precipitated 

 by zinc from acid solutions. Copper and the other well-known 

 metals reduced by zinc precipitate well enough, but nickel, 

 cobalt, iron, &c., do not. If, however, ammonia was added to 

 their solutions the precipitating power of the zinc was rendered 

 as efficient as under ordinary circumstances it is with copper, &c. 

 The zinc was used in the shape of filings, and the author remarks 

 that the metals precipitated by it under the above circumstances 

 present a beautiful metallic appearance, and are in a weighable 

 form. — On the action of the organic acids and their anhydrides 

 on the natural alkaloids (Part HI.), by G. H. Beckett and C. 

 R. Alder Wright. The authors in this paper treat first of the 

 action of acetic anhydride on the polymerides of codeine and 

 morphine (dicodeine, tetracodeine, and tetramorphine being 

 considered, further also the action of ethyl iodide on tetraco- 

 deine and octacetyl-tetracodeine) j they then speak of isomeric 

 diacetyl morphines, and of the action of ethyl iodide onacetylated 

 morphine, codeine derivatives, ^and analogous products. The 

 compounds treated of in the latter division are diacetyl-codeine 

 ethiodide, tctracetyl-morphine ethiodide, a-, j8-, and 7- diacetyl* 

 morphine ethiodide, dibutyryl-codeine ethiodide, tetrabutyryl- 

 morphine ethiodide, dibutyryl-morphine ethiodide, dibenzoyl- 

 codeine ethiodide, tetrabenzoyl-morphine ethiodide, and o dia- 

 cetyl-dibenzoyl-morphine ethiodide. Finally, there is an 

 account of the action of ethylate of sodium on acetylated 

 codeine and morphine. — The Journal, as usual, contains nume- 

 rous abstracts from other serials. — The May number contains the 

 following papers : — Further researches on bilirubin and its com- 

 pounds, by Dr. J. L. W. Thudichum. This is a most elaborate 

 paper, and we must refrain from entering on its details, confining 

 ourselves to a mere outline of its contents. First, the author 

 gives an account of the behaviour of bilirubin with the halogens, 

 and in turn speaks of mono- and dibromo-bilirubin, the tri- and 

 tetrachloro-bilirubin (with iodine there is no reaction at 80° to 

 100°). Then Dr. Thudichum proceeds to consider the operations 

 made by chemists on bilirubin, prior to his own. He then 

 describes some experiments bearing upon the alleged transforma- 

 tion of bilirubin into the colouring matter of urine, and treats of 

 Maly's hydrobilirubin, urochrome spectra, and the spectra of the 

 chemolytic products of bilirubin. We then have an account of 

 experiments made with Jaffe's product, with which Maly com- 

 pared his biliary product more particularly. Jaffe's product was 

 obtained from febrile persons, and Dr. Thudichum points out 

 that a source of error must here be eliminated, namely, the 

 abnormal product urerythrin. He gives the spectrum and a new 

 reaction of this compound ; finally, there is a note on Jaffe's 

 urobilin. The paper ends with a summary of conclusions against 

 the alleged metamorphosis, and with some remarks on the 

 author's theory of bilirubin and bilirubates, and on Stiideler's 

 hypothesis regarding the same. — On calcic hypochlorite from 

 bleaching powder, by Charles T. Kingzett. This treatise turns 

 on the chemical constitution of bleaching powder, on which sub- 

 ject the opinions of eminent chemists are at variance. The 

 author describes four experiments which he made with a view to 

 bring light into the matter, but he was not completely successful. 

 Although his experiments may be regarded as a perfect proof of 

 the body being in mass hypochlorite of calcium, yet he is never- 

 theless reluctant in being too positive on the subject, and recom- 

 mends further investigation. — On a simple method of assaying 

 iron, by Walter Noel Plartley. The principles on which this 

 method depends are (i) The abolition of weights by exactly 

 balancing a quantity of the ore to be examined against pure iron 

 wire. (2) The reduction of inaccuracies in weighing by making 

 the solutions of the iron and the ore up to the same volume, and 

 taking a fraction (about jV) of the liquid for experiment, whereby 

 the error of the balance is diminished j^. (3) The reduction of 

 all other experimental errors to a minimum by putting com- 

 parable quantities of both ore and pure iron under precisely the 

 same conditions. There is the usual number of abstracts in this 

 part. . 



