HARDWICKE'S SCIENCE-GOSSIP. 



243 



published in a late number of the " Proceedings of 

 the National Museum." Each kind of wood is repre- 

 sented by a polished panel about nine by twelve 

 inches in dimensions, upon which are painted in 

 colour accurate delineations of the leaves, flowers and 

 fruit of the tree. Each panel is framed between 

 strips of wood sawn from the outer portion of the 

 tree and covered with bark, and is provided with 

 corner-pieces in the shape of round blocks cut 

 transversely from branches an inch or more in 

 diameter. 



Deserving of special mention is a fine collection of 

 cinchona barks, presented through Messrs. Schieffe- 

 lin & Co., of New York, by the firm of Howard 

 and Sons, of London, which comprises thirty- five 

 specimens of carefully identified barks from the 

 cinchona plantations of India, Ceylon and Java, 

 where the cultivation of the various species of 

 cinchona-tree has become an important industry ; 

 important not only to those engaged in it, but to 

 mankind in general, as giving the assurance of a 

 regular and unfailing supply of this most valuable of 

 all known remedies. This collection of East Indian 

 barks is supplemented by specimens of the usual 

 commercial barks from South America ; by cultivated 

 barks from Mexico, and by barks and herbarium 

 specimens of the flowering branches of the officinal 

 species of cinchona from the Royal Gardens of 

 Calcutta. It is hoped that some public-spirited 

 manufacturing chemist will undertake the preparation 

 of the corresponding series of the opium products. 



Mineral waters will also find a place in this section, 

 and an extensive contribution, representing most 

 American springs, has already been made by the 

 Schaeffer Mineral Water agency. 



The Museum will feel grateful to any druggist or 

 other person who shall assist in the completion of this 

 standard collection, and invites the contribution of 

 any articles rare and curious which belong to the 

 department that has been broadly outlined in the 

 present article, and the value of which to pharmacists 

 and medical men is very great. 



An observer recommends the locomotive as a cheap 

 hygrometer for people living near railroads. When the 

 escaping steam remains long suspended, the air is near 

 its point of saturation with moisture ; but when the 

 steam quickly disappears, as if swallowed up, the 

 weather is dry, and there is little prospect of rain. 

 "On a warm summer day," he writes, "I have 

 seen a passenger train ascending a gradient under full 

 pressure without giving the least sign of its motion, or 

 allowing the least trace of steam to escape. At other 

 times the cloud of steam was ten or twelve feet in 

 length, in certain cases it was as long as the train 

 itself, and in very damp weather it extended a long 

 way beyond the rear of the trai n." 



SLUG GOSSIP. 



By Dr. J. W. Williams, M.A., Editor of the 

 Naturalists' Monthly. 



\_Continucd from page 222.] 



Fam. 2.— Limacid^:. 



GEN. Limax, Lister ; 1678. — De Ferussac, in his 

 " Histoire des Mollusques," was the first to 

 separate the limaces from the arions ; up to this time 

 they were confounded together. According to Leydig, 

 the internal shells of the limaces consist of more or 

 less calcified cuticle and covered by the corium of the 

 back ; this is in a paper in Arch. f. Nat. xliii. p. 

 209-264, entitled, "Die Hautdecke und Schale der 

 Gastropoden nebst einer Uebersicht der einheimischen 

 Limacinen," to which the reader may refer if he should 

 wish to look up the structure of the integument of 

 the terrestrial and fresh-water mollusca. A more 

 lengthened account would not come within the con- 

 fines of this paper. 



L. maximus, Linn. 1758. — An albino of this slug 

 has been described by Paul Fischer in the French 

 Journal of Conchology, on page 299 of the twenty- 

 eighth volume. When irritated, maximus dilates its 

 shield. The reader will have noticed, no doubt, very 

 often little mites running over the body of this 

 creature, and not only "of this creature" but of 

 Arion ater also ; these were first discovered by 

 Reaumur, in 1 710, and mentioned by him in the 

 Mem. Acad, des Sciences, to be afterwards called by 

 Gmelin Acarus Limaaim. They are now, however, 

 known to us as Philodromus Limaaim, a name given 

 by Jenyns, in the "Magazine of Natural History," 

 vol. iv. 538 and fig. 109. They appear to inhabit 

 the interior of the creature, gaining their exit to the 

 outer world by means of the respiratory orifice, and 

 there they run without any seeming inconvenience to 

 the slug hither and thither over his body, with an 

 astonishing rapidity. The wonder to me is that they 

 are not impeded in their exertions by the slime of 

 their host ! The dental formula of L. maximus is 



2 — : — !_2_. I believe Moquin-Tandon says he has 



found one specimen in the Jardin des Plantes twenty 

 centimetres in length. 



L. cincrco-niger, Wolf. D. — Sochrezewer (Z. wiss. 

 Zool. xxxv. pp. 30-46) has made some very interesting 

 experiments on this species with oil and turpentine, 

 the result of which are the conclusion, that the 

 olfactory organ is situated in the pedal gland and not 

 in the tentacles, as La Pluche, Moquin-Tandon, and 

 Velten supposed, a fact which corresponds to the 

 previous conclusions of Leidy and Deshayes. 



L. flavus, Linn. — Mr. Bouillet and M. Morelet 

 have made the interesting observation, that L. flavus 

 changes in colour from a bright yellow to a dull 

 clive-green if tormented or kept in confinement. 



M 2 



