6o4 



NA TURE 



[October 26, 1905 



The paper is a valuable contribution of facts to the 

 solution of questions of much interest, and M. Pictet's 

 conclusions as to the causes of the results he describes 

 are well worthy of the consideration that they will 

 doubtless receive. It is to be presumed that he took 

 all proper means to isolate the influences he applied 

 from other influences, but his arguments would 

 perhaps have gained in force if he had stated in detail 

 what steps he had taken to ensure this isolation. For 

 example, in his experiments on the colouring assumed 

 by larvae, though he is acquainted with the experi- 

 ments of Prof. Poulton and others, showing the un- 

 doubted effect of a few coloured surroundings on the 

 colouring of the larvee of many species, it does not 

 appear what precautions were taken to exclude the 

 operation of such surroundings ; nor in the experi- 

 ments on the duration of the pupal stage when the 

 larval " diapause " was shortened, or in the humidity 

 experiments, does it appear that the temperatures 

 during all the time of the pupal stage were noted ; 

 it is known that a very moderate difference in 

 temperature will make a difference of many days in 

 the duration of this period. One may venture to 

 suggest, also, that in the continuation which it is 

 hoped M. Pictct will make of his valuable experi- 

 ments he will give as far as possible the whole 

 number of the insects in the broods at their commence- 

 ments and the whole number of perfect insects reared 

 — in the great majority of cases only percentages are 

 given ; also that he will state whether the whole 

 or nearly the whole of those reared were similar in 

 appearance to those figured, and whether there was 

 any considerable proportion substantially different. 



There appears to be one error to which, as it has 

 not the character of a mere slip, and therefore has a 

 bearing on the arguments used, it is necessary to 

 direct attention. The larvse of the first generation of 

 the year of I', urticae are at p. 94 mentioned as 

 coming from butterflies which "have probably passed 

 the winter in the chrysalis stage," and at p. 81 

 " certain Vanessas " are spoken of as being able to 

 pass the winter in the egg, chrysalis, or winter stage. 

 Surely V. urticae hibernates only as an imago, 

 wherever there is a real winter, as is the habit of the 

 Vanessas generally. Again, fifteen to twenty davs is 

 stated as the usual period of the lar\'al life of 

 Argynnis paphia; in England this hibernates as a 

 very young larva, and feeds up, very quicklv it is 

 true, during April, May, and June, appearing as an 

 imago in July or early .August, and this is its usual 

 habit on the continent of Europe. 



F. Merrifield. 



CHEMISTRY IN THE SERVICE OF THE 

 STATE.' 

 "j N the year 1S40, the Legislature made an interest- 

 ing fiscal experiment. It repealed all previous 

 enactments against the adulteration of tobacco, and 

 permitted any ingredients, " except the leaves of 

 rrct-i, herbs, and plants," to be added to that article 

 in the course of its preparation. Tlie result was that 

 tobacco speedily became grossly adulterated ; in two 

 years the consumption had decreased bv more than 

 a million pounds; and, since tobacco is a heavilv 

 taxed commodity, the Exchequer suffered severely. 

 So serious a loss had to be promptlv stopped ; hence 

 in 1842 the prohibition of adulteratiori was re-enacted. 

 To help in making the prohibition effective, the Com- 

 missioners of Inland Revenue fitted up a small labor- 

 atory, the staff of which, consisting for some time 



1 " Report of the Principal Chemist upon the Work of the Gove 

 I..iboratory for the Year enaing March 31, 1905 " Official Publi 

 Cd. 2591 . Price ^(f. 



NO. 1878, VOL. 72] 



of one person onh-, was occupied solely in detecting 

 fraudulent additions to tobacco. 



Such was the modest origin of the chief branch 

 of the institution which now undertakes nearlv all 

 the analytical and consultative chemical work required 

 bv the various Government departments. Another 

 branch, the Customs Laboratory, ma\' be said to owe 

 its inception chiefly to the Sale of Food and Drugs 

 -Act, 1875, which laid upon the Board of Customs 

 the dutv of supervising the quality of imported tea. 

 The two branches were afiiliated in 1894 under one 

 head. 



How considerable the business of the laboratory 

 has now become may be gathered from the recently 

 issued report of the principal chemist, describing the 

 work of the department during the last financial year. 

 From this it appears that the number of samples 

 analysed in that period was no less than 138,508. 

 Of these, 49,751 were examined in the Customs 

 branch, and the remainder, 88,757, in the main 

 laboratory at Clement's Inn Passage. 



What, however, more particularly strikes one is 

 the wide range of interests, both of the State and of 

 the individual, which are touched at one point or 

 another bv the chemical activities of the department. 

 We extract from the report a few notes which may 

 serve to illustrate this, and to indicate the nature of 

 the questions dealt with. 



Dealing first with the Customs, the ultimate aim 

 of the various analyses is, of course, to facilitate the 

 just assessments of Customs dues. This, however, 

 involves the testing of many articles which are not 

 themselves dutiable. For instance, genuine cider is 

 free of duty. .A temptation is thus offered to an un- 

 scrupulous wine importer, since by labelling his wine 

 as " cider " he mav, if undetected, get it passed into 

 the country without payment. As a matter of fact, 

 out of 154 samples examined during the past year, 

 10 represented importations of so-called " cider " 

 which was found to be chargeable as wine, and 

 another had to pay duty as a spirit preparation. 

 .Again, crude methyl alcohol is admitted free, but if 

 purified so as to be potable must pay the spirit duty. 

 In 31 cases out of 256 the substance was, in fact, so 

 pure that the full alcohol rate was levied. 



As compared with the previous year, there has been 

 a notable decrease in the number of certain beer, 

 wine, and liqueur samples; this is attributed to 

 diminished consumption of alcoholic beverages. On 

 the other hand, samples of tea show a considerable 

 increase — from 2345 to 3260 — in spite of an augmented 

 tea-duty. For various reasons, 316 of these speci- 

 mens of tea were objected to, and 7 were condemned 

 as unfit for human food. 



Among other items of interest, we note that facili- 

 ties are given by the Customs authorities for the 

 utilising of waste tobacco in the preparation of sheep 

 dips and similar articles. It appears that nicotine 

 is supplanting arsenic as the active principle in such 

 products. 



The very high duty on saccharin — 20s. per pound — 

 involves, the principal chemist remarks, a careful 

 outlook for this substance in the most unlikely places. 

 617 samples of articles which might have been vehicles 

 for its fraudulent introduction were tested, and 55 of 

 the number were charged the duty as being either 

 saccharin or substances of like nature and use. 



In the laboratory at Clement's Inn Passage, the 

 business is classed as (i) Revenue work; (2) work for 

 other Government departments ; and (3) the analysis 

 of samples referred by magistrates to the Government 

 chemists in disputed cases under the Sale of Food and 

 Drugs Acts. The examinations of excisable articles 

 are devised to secure the revenue accruing from beer, 



