HA R D WICKE'S SCIENCE- G OS SIP. 



233 



All the southern districts of Russia have been 

 suffering greatly from the Hessian fly. This insect 

 .made its appearance during the present summer in 

 Essex and Hertfordshire. 



The celebration of the centenary of New South 

 Wales takes place in 18SS. The Government invite 

 the members of the British Association to hold their 

 annual meeting for that year in Sydney. The invita- 

 tions will be extended to all the British Universities, 

 literary, scientific, and art societies. 



The British Association meeting is over, and it has 

 been unusually successful from a scientific point of 

 view. The address of Professor Crookes, F.R.S., 

 cannot fail to be a fresh starting-point, both for 

 speculation and investigation in chemistry and 

 physics. Professor Crookes is of opinion that the so- 

 called elements were evolved from a common kind of 

 matter, just as biologists teach that all forms of 

 animal and vegetable life that peopled the world in 

 past geological ages, and which still inhabit it, were 

 derived ixom protoplasm. This primitive and original 

 basis of matter may be identical with that unknown 

 and mysterious substance seen in the corona of the 

 sun and known as Helium ; but Professor Crookes 

 prefers to call it Protylc. The theory of the gradual 

 evolution of the seventy chemical elements, begin- 

 ning with Helium, then proceeding to hydrogen, &c, 

 was worked out in the most brilliant manner. 



Professor D'Arcy Thompson exhibited some 

 skulls of embryo narwhals and other cetacea, about 

 an inch long. He argued that the specimens showed 

 very primitive features not consonant with the view, 

 that the whales are most closely allied to the hoofed 

 mammals. 



Mr. L. Upcott Gill continues to issue his 

 sevenpenny parts (illustrated) of the " British Cage 

 Birds " and " Fancy Pigeons." Thirteen parts have 

 now appeared. 



We have received copies of the useful catalogues 

 of second-hand scientific books from Messrs. W. 

 Wesley, Essex Street, Strand, and W. P. Collins, 

 157 Great Portland Sreet. 



A periodical we are always pleased to receive is 

 the " Rochdale Field Naturalists' Journal." 



The celebrations in connection with the Chevreul 

 ceremony took place in Paris the last Tuesday in 

 August. M. Chevreul was born at Angers on August 

 31st, 1786, and he is still well, and never fails to 

 attend the Monday meetings of the Academy. 



We regret to record the death of Dr. Wakley, 

 editor of the " Lancet," on August 30th. 



Professor Barff, the well-known chemist and 

 author, has justdied, aged 63. 



MICROSCOPY. 



Staining Vegetable Sections. — As some of 

 your readers may have found that on lifting thin 

 vegetable sections from one fluid to another, so many 

 times as it is necessary to do in double staining them, 

 they are liable to get broken, it may interest them to 

 know a method I have found very successful of 

 avoiding this difficulty. After the sections have been 

 cut and the paraffin removed from them, they should 

 be put in specimen tubes (those I use are an inch long 

 and I in. wide). A piece of muslin should be tied 

 over the mouth of each tube. To bleach the sec- 

 tions the tubes should be put in chlorinated soda, 

 or into a bottle containing water, through which 

 chlorine should be passed. After bleaching, the tubes, 

 (still keeping the muslin over the mouths) should be 

 put in a large basin of water, and the water changed 

 several times, then the different stains can be poured 

 into the tubes and poured out again. The sections can 

 be bleached, washed, put in a mordant stained with 

 carmine. Tut in an acidulated water to fix the carmine 

 stained with aniline green, cleared in benzole or 

 oil of cloves, without once ' handling them. — Fred 

 Beddow, Derby. 



Wilks' Cell. — It is somewhat difficult to give 

 R. S. P. the information he seeks on the manner of 

 using the Wilks' cell, without first knowing how 

 advanced he may be in the preparation of objects 

 without pressure. It requires a considerable amount 

 of care to get the objects ready for the cell, but when 

 this is done the mounting of them is the easiest part. 

 If R. S. P. refers only to this latter part, he will find 

 no difficulty if he proceeds as follows. Take a cell and 

 see that it is no deeper than the object requires. If it 

 is too deep it can easily be flattened between two 

 pieces of glass by pressure, until the exact depth is 

 gained. All that remains then to be done is to place 

 it on a clean slip, fill it with thick balsam, and, 

 immersing the prepared object, put on the cover 

 glass. In using the thick balsam, numerous air 

 bubbles will most likely appear in the cell. This is a 

 small matter, for if kept in a warm place they will 

 gradually work to the edge and disappear. If R. S. P. 

 wishes for anything like full information on the 

 preparation of objects for the cell, I fear it cannot 

 be given without devoting at least one article to the 

 subject. The Wilks' cell is a very useful introduction, 

 and deserves to be largely used. Prior to its inven- 

 tion I have frequently extemporised one from a 

 vulcanite cell, that sufficiently answered the purpose, 

 although at the cost of time and trouble. Still I 

 think the cell is open to improvement, and would 

 suggest that it had at least twice the number of 

 elevations, or, perhaps better still, was corrugated, as 

 in its present form the cover glass is likely to get 

 broken unless well banked up with edging colour, as 

 there is so large a space between the supports. — 

 J. IV. Neville, I/andsivorth, Birmingham. 



