HA RD WICKE'S S CIENCE- G OS SIP. 



"5 



Staining Nerve and Muscle. — As to the most 

 perfect mode of demonstrating the distribution of 

 nervous structures microscopists differ. Klein and 

 Cohnheim consider that preparation stained with 

 chloride of gold will show the ultimate ramifications 

 of nerve fibres ; whilst Beale (" Microscope in Medi- 

 cine ") says he has never been able to demonstrate 

 the final distribution of nerve fibres by the chloride 

 of gold stain, but did so by specially preparing the 

 specimens and then acting on it with acetic acid. 

 Soak the specimen in glycerine for some days, 

 beginning with a weak watery solution, and gradually 

 increasing the density of the fluid, finishing with 

 Price's glycerine, sp. gr. 1240. Now wash the 

 tissue with glycerine containing 5 drops of acetic acid 

 to the ounce. Put a drop of glycerine, containing 

 2 drops of acetic acid to the ounce, on a clean slide, 

 place the tissue in it, and apply a thin cover glass. 

 Examine with a high power. The prolonged action 

 of the acid causes the nerve fibres to become slightly 

 granular, and thus to be easily distinguished from the 

 tissues in which they ramify. The muscular structures 

 of the specimen will also be shown by this mode of 

 preparation. — Dunley Owen, B.Sc. 



Examination of Fibres, &c. — The " American 

 Monthly Microscopical Journal " for March contains 

 a translation, from " Etudes sur les Fibres," by M. 

 Vetillart, in which flax, hemp, nettle, cotton, jute, 

 phormium, and other fibres are classified and their 

 appearance, dimensions, &c, described. The prelimi- 

 nary directions given, however, scarcely seem full 

 enough, but the translation is not stated to be a 

 continuation. 



Crystals for the Polariscope. — It is most 

 vexatious that some of these attractive preparations 

 should be so fleeting. From my own experience 

 this applies to some only, for others appear to be 

 just as enduring. I once had a somewhat large 

 collection of objects of this class, but as they 

 deteriorated I took them to pieces until only a few 

 now remain. All crystals containing sulphate of 

 copper lost their sharpness in a few weeks, and were 

 almost useless in a few months. Sulphate of iron 

 also lost its sharpness, but afterwards appeared to 

 get no worse, while crystals of oxalurate of ammonia, 

 hippuric acid, and salicine are in every respect as 

 beautiful and perfect as when prepared some seven or 

 eight years ago. That dampness will destroy these 

 objects I have had abundant proof; for, once wishing 

 to finish off two slides in a hurry, and my brown- 

 cement being dried up, I ran a ring of gum-water 

 round the cover-glasses and afterwards finished them. 

 Shortly, the crystals could be distinctly seen 

 dissolving from the outer edge, their gradual dis- 

 solution towards the centre being very interesting 

 under the microscope. A friend who devoted much 

 time to this branch of microscopy once told me that 



pure balsam would preserve crystals, that would 

 gradually dissolve if the balsam contained turpentine. 

 Perhaps some readers can say whether this is so, or 

 whether gum dammar or copal would be a better 

 preservative, for any method of micro preparation 

 that is not permanent must be very unsatisfactory. — 

 J. W. Neville, Handsivortli. 



I venture to ask you to give me space for an appeal 

 to brother microscopists in various parts of the world. 

 I am desirous of obtaining samples of mud from 

 abroad, especially from tropical and sub-tropical 

 countries in South America and elsewhere, with a 

 view of cultivating them here. I hope, by so doing, 

 to bring to light many new forms, both of infusoria 

 and rotifera, as the power which these creatures have 

 of protecting themselves against changes in external 

 conditions is so great. The mud should be taken 

 from the surface of the bed of a pond or lake, or 

 some similar body of water, preferably from the 

 surface of the part which dried up last, and should 

 be labelled with the name of the locality. A few 

 ounces will be amply sufficient from each spot, and I 

 shall be glad to refund any expense incurred in 

 forwarding, and to communicate results to the 

 senders. — Edward C. Bousficld, 363, Old Kent Road, 

 London, S.E. 



ZOOLOGY. 



Astarte Borealis. — I have received amongst 

 other shore-shells from the beach at "Warkworth, 

 Northumberland, a valve of this shell with a very- 

 fresh epidermis. Its condition resembles that of 

 specimens taken from a fish's stomach. — R. D. 

 Darbishire, in " The Journal of Conchology." 



The Proceedings of the Holmesdale 

 Natural History Club for 18S1-2-3, recently 

 published, contains an interesting paper by Mr. H. M. 

 Wallis, of Reading, on " Character, as one of the 

 Causes of the Rarity or Abundance of Different 

 Species of Birds." In it the author points out how 

 the different qualities of brute courage, "coolness," 

 teachableness, and adaptiveness, operate in different 

 cases for or against their possessors in the struggle 

 for existence. Sparrows drive martins from their 

 nests and pigeons from their food, and in the winter 

 during stress of weather such boldness would serve 

 the sparrow in good stead. The amount of disturb- 

 ance birds will tolerate during nesting varies with 

 different species, and the more timid a bird is the less 

 will be its chance of bringing up its young. The 

 Great Auk has been exterminated through its clinging 

 to its traditional breeding sites while the Greater 

 Shearwater escapes in consequence of its solitary 

 habits, so that nothing is known of its nest or eggs. 

 Other instances of the adaptive faculties of birds are 

 given by Mr. Wallis, whose paper is most readable 



