7 6 



HARDWICKE'S SCIENCE-GOSSIP. 



people. In these cases the free alkali combines with 

 the exuberant grease. In common yellow soap more 

 or less of the fatty acid is replaced by resin. 



The novelty to which I refer is the use of a centri- 

 fugal machine or drum, which is made to rotate very 

 rapidly while containing the crude soap before it 

 has been cooled. All the alkali or salt is thereby 

 separated, and a larger quantity of the water ; 

 the soap is very dense and perfectly neutral, and 

 therefore non-irritant. I may add, by way of warn- 

 ing, that among the fancy soaps is a vile com- 

 pound, in which the fatty acids are more or less 

 replaced by silicic acid. It is very smooth, lathers 

 admirably, but treats tender skin most cruelly. One 

 of the indications of the adulteration and of saline 

 impurities generally is the efflorescence of very pretty 

 crystals orr the surface of the soap as it dries. 



A more recent contribution of science to domestic 

 economy has been discussed by the Hygienic Council 

 of the Department of the Seine at Paris. It is the 

 use of vaseline as a substitute for butter or fat in 

 pastry. It appears that the chief motive of the pastry 

 cook in adopting this " improvement " (?) is to obtain 

 a. pastry that will keep longer. From the tradesman's 

 point of view this may be a desideratum, but to the 

 consumer it is not so advantageous, seeing that this 

 mineral grease is absolutely indigestible. It may slip 

 through the digestive organs by virtue of its 

 lubricating properties, and carry with it the particles 

 of flour, sugar, &c, which it envelopes, but it cannot 

 be assimilated, and probably protects the materials 

 with which it is incorporated from the action of the 

 digestive solvents. The strongest mineral acids do 

 not disturb vaseline, neither do the most caustic 

 alkalis saponify it. In the pastry it comes as vaseline 

 and goes as vaseline, and probably does mischief in 

 the course of its journey through the body. " The 

 Council therefore advises that its use for pastry 

 making shall not be permitted in France." Let us 

 hope that such use may not be permitted in England. 



While M. Perrotin, director of the Nice Observa- 

 tory, was making an observation on Hyperion, one 

 of the satellites of Saturn, the object suddenly dashed 

 to the right of the spider-line of the telescope, and 

 then returned. It was the telescope that moved, and 

 the earth that moved the telescope. A slight but 

 sharp earthquake tremor occurred. This incident 

 suggests a delicate means of measuring such move- 

 ments. 



We have received the first number of a new 

 monthly periodical, the "Journal of Mycology" 

 (Manhattan, Kansas). It is intended to be a medium 

 for the publication of matter of mycological interest ; 

 to note the discovery of new species of fungi, to give 

 an account of the literature of the subject, and so 

 assist in the extension of North American mycology 

 in general. 



THE VARIATION AND ABNORMAL DE- 

 VELOPMENT OF THE MOLLUSCA. 



THE variation of the Mollusca is an exceedingly 

 interesting subject, but it is as vast as it is 

 interesting. There seems to be hardly a species 

 which, if sufficiently studied, does not present here 

 and there some marked difference from what is known 

 as the typical form ; and some, as Helix nemoralis, are 

 so variable, that two exactly similar specimens are 

 rarely found ; And this variation does not seem to 

 rest on mere chance, but varieties are often local, 

 abundant at one place, and not to be seen in the 

 surrounding country : and, strangely enough, this 

 localness seems also to be to a certain extent peculiar 

 to what are generally called mere monstrosities. I 

 mean the sinistral, scalariform, and decollated forms. 

 Miss Hele, in Science-Gossip, records the occurrence 

 of three sinistral Helix aspersa, and two H. hortensis, 

 all in the same lane, and I cannot think that this was 

 purely accidental ; there must have been some reason 

 for these shells becoming reversed, but what that 

 reason may be, I cannot imagine. On Chislehurst 

 Common I took a specimen of the monst. scalariforme 

 of Limiuca stagnalis, having the whorls almost 

 disunited, and the suture between the fourth and 

 body whorl forming an acute angle. This specimen 

 was found in a very small pond, where the typical 

 form of L. stagnalis does not occur, but the pond is 

 crowded with a variety, which is smaller than the 

 type, and has a deeper suture. In the same pond my 

 brother took another scalariform L. stagnalis, and he 

 also found a third specimen in a pond not far off. 

 Another brother (L.M.C.) has taken L.peregra, monst. 

 scalariforme at St. Mary Cray, two miles from 

 Chislehurst, and a scalariform Helix aspersa on 

 Chislehurst Common. Whether there is any connec- 

 tion between the occurrences of these scalariform 

 shells I do not know, but, if so, I suppose it must 

 be due to the soil, or possibly, but not probably, to 

 some parasite. I fancy the food has little or nothing 

 to do with it, but I may as well mention that the 

 pond in which the two scalariform L. stagnalis were 

 found, contained Ranunculus aquatilis, and Pota- 

 mogeton crispus, and the jjond in which the other one 

 was found contained Anacharis. 



And now for an instance of decollation. On 

 Barnes Common I have found Bythinia tentaculata, 

 monst. decollatum, Liiimcea stagnalis, monst. decolla- 

 turn, and a decollated specimen of L. palustris* The 

 decollation is most marked in the Bythinia, and less 

 so in the Limncea. Now in the instance of these 

 Barnes specimens, I think there cannot be much 

 doubt that the truncated spire is caused by a want of 

 calcareous material in the water, and that, if a 

 number of them were introduced into a pond contain- 

 ing a sufficient amount of carbonate of lime, the next 



* My brother (S.CC.) has also taken the decollated form of 

 L. peregra. at Barnes. 



