l62 



NATURE 



\_yune 27, 1872 



0'27 mgrni. of ammonia ; that we took 5-5 mgrm. of strychnine 

 and obtained o'jom^nn. of ammonia; and that we took 10 mgrm. 

 of sulphate of quinine and oli'.ained o'45 nigtm. of ammonia. 

 The absolute errors, therefore, were — 



Milligrammes of 

 Calculated. Found. Error. 



Papaverine 0-25 0-22 0-03 



\. Sulphate of cinchonine 048 057 009 



II. ,, .. o'-24 027 o'03 



Strychnine o'2S 030 o'02 



Sulphate of quinine o'45'5 0^45 0'oo6 



giving a mean error of 0'035 mgrm. 



I have to remark, in reference to these five examples, that they 

 are not cases selected by me to e.-chibit the accuracy of our pro- 

 cess, but cases picked out from a great number, in order to ex- 

 hibit what takes place under the most unfavourable circum- 

 stances. In contrast with these are Frankland and Armstrong's 

 six de'.erminations, five on urea and one on hippuric acid, given 

 by themselves as exemplifying the accuracy of their method, and 

 showing a mean error of o'35 mgrm. of nitrogen — ^just ten times 

 as much as ours under the most unfavourable conditions. 



I observe you say that the amount of ammonia obtainable from 

 albumen by the action of alkaline permanganate is influenced by 

 the digree of concentration of the solution, the amount of heat 

 applied to the retort, and consequent rate of disdllation, and the 

 time to which the solution is exposed to the action of the alkaline 

 permanganate. 



It would be just as true and as much to the point to say that 

 the amount of carbonic acid obtainable from sugar depended on 

 the amount of oxide of copper with which it is mixed, and the 

 length of time to which it is expr.se 1 to a red heat. 



I am able to affirm most positively that there is no difference 

 in the yield of ammonia from albumen, whether the solution be 

 of a certain strength or six times as strong, or whet'ier the dis- 

 tillation be rapid or slow ; and in proof of this 1 refer to a set of 

 experiments on albumen, published in 1S67. If the action of the 

 permang.inate be pushed to the ultimate limit, the yield of am- 

 monia is constant. 



Your assertion that water which has been distilled from per- 

 manganate, and gives no reaction with the Nessler test, yields 

 ammonia on being again distilled with permanganate, will not 

 astonish persons who have had experience in the working of our 

 process. The explanation of this fact is now, I believe, tolerably 

 well understood, and is simply this : that when water contains 

 so minute a quantity of ammonia as not to impart a colour when 

 100 cubic centimetres of it are treated with Nessler test, it may 

 still contain sufficient ammonia to yield a perceptibly ammoniacal 

 distillate if one litre be made to yield 100 cubic cntimetres of 

 distillate. 



In conclusion, you mention some difficulties in applying our 

 process to the effluent water from sewage farms. I will not, on 

 this occasion, describe how these difficulties are overcome. 

 Suffice it to say that they have been overcome by very simple 

 and obvious means. J. Alfred Wanklyn 



II, Harrington Street, London, June 17 



Parasite of the Beaver 



May I occupy a few lines of your valuable space for a brief 

 note upon the singular parasite of the beaver, Plaiypsylla castoris 

 Ritsema {Pla/ypsyllus castorintis Westwood) ? 



On the kind application of Messrs. Wayers and Roelofs, of 

 Brussels, Mr. Ritsema very courteously presented me, some 

 months ago, with a pair of this insect, the remarkable characters 

 of which seem to deserve a more extended notice than has been 

 given by himself or by Prof. Westwood, who almost at the same 

 time described it from specimens obtained from a different 

 source. 



The former has classed it with the so-called suborder, Siictoria, 

 or Aphaniptcra, as a family or series equal in value to the Pidi- 

 cidcB (fleas, jiggers, &c.), while the latter considered it so pecu- 

 liar as to represent a new order of insects, which he named 

 AchrciopUra. 



After a careful study of a series of beautiful dissections made 

 for me by my friend the Rev. A. Matthews, I have to dissent 

 from both of these views, and to regard it, in accordance with 

 my imprc-sions at first sight, as Culci'/lirotis. 



The appearance of the msecc istuch as to mark it, on the most 

 superficial inspection, as a distinct family. In the wonderful 



structure of the mentum, with three immense posterior lobes, it 

 shows an affinity, though remote, with the singular genus, Lep- 

 tintis, which is also the type of a family {ride Le Conte, Proc. 

 Acad. Nat. Sciences, Philadelphia, 1S66, p. 368). But the 

 lateral lobes in Plaiypsylla, broad triangular processes, are in 

 Lcptiinis only narrow spines, projecting in the same manner 

 over the gular plate. 



In the form of the antenna; it resembles Gyi-inus and Paniiis, 

 and in other less important parts of the body it has unmistakable 

 affinities with various members of the Clavicorn series, such as 

 Staphylinidce, Silphidic, and Corylophida:, though especially with 

 Ti-uiiopterygida:, in the very extraordinary genus Liniulodcs, 

 Matthews. 



A very rare character is the reception of the antenna; in cavi- 

 ties on the dorsal surface of the prothorax ; such characters are 

 found in Pliyseiniis of the Byi-rliidir, Mychocerus Er. , the affini- 

 ties of which are doubtful, and in Uscchus Motsch. of the Tcnc- 

 brionidic. In those three genera tiie antennal cavities are round 

 foss.x, while in Plaiypsylla they are grooves extending along the 

 whole lateral margin. 



My object in the present note is not so much to express an 

 opinion on the systematic position of this wonderful animal (which 

 I will discuss fully in an illustrated memoir now in preparation), 

 as to call the attention of your readers to the possible occunence 

 of similar epizoa on other aquatic mammals, especially rodents. 



The complex affinities of this genus indicate that it either was 

 in former times, or is at present, a widely distributed type. The 

 European beaver, the capybara, and the musk rat, may, per- 

 haps, when examined, be fo:md to support allied forms. 



I will conclude by observing that the insect has no organs with 

 which to perforate the substance of its patron, and cannot eat 

 living tissues or fluids ; it is, therefore, not a parasite in the strict 

 sense of the term, but an inquiline, living upon effete material, 

 perhaps epidermal scales. The larva should be diligently sought 

 for by those that have the opportunity, both in the houses and 

 on the bodies of the beavers, as a knowledge of the development 

 and transformations will be of importance in recognising more 

 fully its affinities. 



I trust that this note may stimulate further investigation on 

 the part of some of your readers. 



Lausanne, June 19 John L. Le Conte 



Vespertilio 



Yesterday a neighbour, in cutting down a very old, wide- 

 spreading broadleaf {Grisdiiiia littoralis), came suddenly on a 

 greac crowd of bats. Whilst he was chopping he noticed that 

 his dog seized something, which he found to be a bat. From a 

 huge hollow limb of the tree seventy-five bats were dislodged ; 

 they fluttered into the bush, keeping just above the ground. 



Ohinitahi, New Zealand, Feb. 14 T. II. PoTTS 



Origin of Cyclones 



I HAVE to thank Mr. Whitmee for his statement about the 

 formation of cyclones at the Samoan and neighbouring islands in 

 the latter part of the Southern summer. It will be seen that 

 though I was ignorant of the fact when I wrote in my former 

 letter on cyclones, it confirms my theory that they originate " in 

 the meeting of the_ trade-winds in the northern and southern 

 hemispheres, at some distance north or south of the equator." 

 The cyclone region in which the Samoan and Fiji islands are 

 situated is probably an extension of that of the Southern Indian 

 Ocean. Joseph John Murphy 



Old Forge, Dunmurry, Co. Antrim, June 17 



THE POPULATION OF THE PHILIPPINE 

 ISLANDS 



ACCORDING to the latest, not yet published, statistics, 

 the Philippine Islands are inhabited by 7,45 1,352 in- 

 habitants, distributed into 43 provinces and 933 cities or 

 v.Uagcs. 1,232.544 pay tribute to the Government, and the 

 number of 7,451,352 is calculated on the supposition that 

 about the sixth part of the whole has to pay tribute. As there 

 exist in all the islands, even in Luzon, independent tribes. 



