HARDWICKE'S SCIENCE-GOSSIP. 



5* 



British species found in Africa, south of the Sahara, 

 are either migratory or were imported by human agency. 



Certain European Lepidoptera are conspicuous in 

 all African collections, and these I regard as belong- 

 ing to the migratory group *— such are Achcrontia 

 airopos (from Natal to Gambia and Kilimanjaro), 

 Sterrha sacraria (Kilimanjaro), Chcerocampa nerii 

 (Natal and Gambia), and the following species in a 

 collection from Gambia — Dciopeia pulchclla, Heliothis 

 peltigera, Plusia ni, Chcerocampa celcrio (a species 

 wandering even to New Caledonia), Sphinx convol- 

 vuli, and Lyccena Bietica. 



T. D. A. COCKERELL. 



West Cliff, Custer Co., Colorado. 



A CHAPTER ON BENZOYLSULPHONICIO- 

 NIDE, OR SACCHARINE. 



By Dr. Alfred Crespi. 



SUCH is the somewhat uncouth and unfamiliar 

 name that will soon be known to every one. 

 It is the scientific designation of that singular 

 sweetening agent which, though known to scientific 

 men for some little time, came prominently before 

 the public in the presidential address of Sir Henry 

 Roscoe, at Manchester, six months ago. Such a 

 name ought to cover properties quite cut of the 

 common run, and when we inform the reader that 

 saccharine— the name it will popularly be known by 

 —is 250, or, it may be, 300 times as sweetening as 

 cane sugar, his curiosity will be aroused. 



Unfortunately, the medical and scientific papers 

 often contain reports, framed in all fairness and 

 goodwill, of marvellous discoveries in electricity, 

 chemistry, agriculture, and medicine, that it is con- 

 fidently promised will revolutionise modern life ; 

 and while we remain on the qui vive, looking out for 

 more information, and hoping soon to profit by the 

 discovery proclaimed in such warm terms, we wait 

 in vain, and the world goes on in its humdrum way 

 much as usual, neither the better nor the worse for 

 the march of scientific discovery. 



It is reassuring to be told that saccharine will not 

 drive cane and beetroot sugar from the field, for those 

 familiar objects of daily use there will still continue 

 some demand; but it will be useful in culinary 

 operations, and as medicine, and as a flavouring 

 agent, and perhaps in other ways. 



Its sweetening properties are remarkable. One 

 grain of the ammoniacal hypo- sulphite of silver will 

 render 32,000 grains of water distinctly sweet ; but 

 one grain of saccharine, according to Professor 

 Stutzer, of Bonn, will sweeten 70,000 grains of 

 water. 



* Vide "Entomologist's Monthly Magazine," March, 1885, 

 p. 233. 



Saccharine is one of the many derivatives of coal- 

 tar, and was very fairly described by Sir Henry 

 Roscoe, in a lecture at the Royal Institution, as "the 

 most remarkable of all the marvellous products of the 

 coal-tar industry." Now when all is remembered 

 that coal-tar has done for mankind in the shape of 

 providing colours, essences, and flavours, in the past 

 thirty years, this is strong praise. 



Saccharine is a white amorphous powder, and when 

 examined under the microscope, is found to have a 

 crystalline appearance. It melts, or fuses, rather, at 

 a temperature of 424 Fahr., and then undergoes 

 partial decomposition, while it gives off a powerful 

 and easily recognisable odour. Placed upon the 

 tongue, in its pure state, it is rather disappointing, 

 as its sweetness is less marked than one would 

 expect. Two explanations offer themselves : in the 

 first place, it is not, in its pure state (nor will even 

 the saliva thoroughly dissolve it) highly soluble in 

 water; and in the second, its strength is so great 

 that it deadens, by its very intensity, the nerves of 

 taste, much in the same way as when we enter a 

 brilliantly-lighted room, on a dark night, we are 

 dazzled from the pupil being widely dilated, or, 

 better still, much as a beam of electric Heht falling 

 from a short distance upon the retina causes confusion 

 of vision and dizziness. 



Saccharine must, therefore, be regarded as an 

 essence, as par excellence the concentration of sweet- 

 ness, and to get its full power needs free and in- 

 telligent dilution. Vanellin, another of the many 

 wonderful products of coal-tar, which is rapidly dis- 

 placing the older and better-known vegetable flavour 

 vanilla, is also overpoweringly pungent, and far 

 pleasanter in a less concentrated form. In cold 

 water saccharine is hardly at all soluble, and although 

 it is more soluble in warm water, it is not till it is 

 mixed with boiling water that it becomes very 

 soluble. The completeness of the solubility is greatly 

 increased by neutralising the fluid in which it is 

 placed, and this can be done most readily by adding 

 carbonate of soda or carbonate of potash, two suffi- 

 ciently familiar articles in most well-to-do households. 

 Saccharine expels the carbonic acid present in the 

 solution, and soda or potash salts of saccharine are 

 formed that taste almost as sweet as pure saccharine 

 itself. Probably for commercial and domestic pur- 

 poses saccharine will soon come into common use in 

 the form of an alkaline powder. Messrs. Burroughs, 

 Wellcome & Co. sent us some tabloids containinjr 

 half a grain of saccharine, and equivalent roughly to 

 a large lump of loaf sugar. We find that it is better 

 to put the tabloid in the cup, and then pour in hot 

 tea, coffee, or cocoa, and after stirring a few time?, 

 adding the milk or cream. The flavour is in no 

 way peculiar, but scarcely as agreeable as cane 

 sugar, though use would soon remove that little 

 objection. 



Alcohol, that powerful solvent of many alkaloids 



