HARDWICKE'S SCIENCE-GOSSIP. 



37 



—April 17, F. Milner, "The Origin of Chalk as 

 shown by the Microscope." May 5, J. M. Kirk, 

 "Animal Life in its Lower Form." June 2, 

 W. Walker, M.R.C.S., "On the Structure of the 

 Organs of Locomotion in Man." 



New Fluid for preserving Organic Sub- 

 stances.— In the " English Mechanic," No. 780, an 

 account is given of a fluid for the preservation of 

 animal and vegetable tissues, which is unique in its 

 excellency. It was invented by M. Wickersheimer, of 

 the University of Berlin. The fluid may be injected 

 into the veins of the object to be preserved by it, or 

 the entire object may be immersed in it ; in either 

 case the elasticity of the tissues, and flexibility of the 

 joints, are preserved. All sorts of vegetable organ- 

 isms may also be preserved in this fluid. A colony of 

 exquisite water Algse, which had been in the fluid for 

 a year, appeared to be growing in the water. The 

 formula for the preparation is as follows : In 3000 

 grammes of boiling water dissolve alum, 100 

 grammes ; common salt, 25 grammes ; saltpetre, 

 12 grammes; carbonate of potash, 60 grammes; 

 arsenious acid, 10 grammes. After cooling and 

 filtering, add to every 10 litres of the solution, 

 4 litres of glycerine, and 1 litre of methylic alcohol. 

 Anatomical preparations that are to be preserved 

 dry, are immersed in the fluid from six to twelve 

 days, according to their size, and then dried in 

 the open air. 



Microscopical Society of Liverpool. — The 

 third ordinary meeting of the twelfth session of this 

 Society was held at the Royal Institution, on Friday 

 evening, March 5, 1880; Dr. J. Sibley Hicks, 

 president, in the chair. Mr. Stuart, of Messrs. 

 Ross & Co., London, exhibited and explained the 

 principle of their new patent microscope, the chief 

 advantage of which consists in a firm thin stage and 

 swinging substage. The paper of the evening was 

 by the president, Dr. J. Sibley Hicks, on "The 

 Eyes of the Arthropoda." Dr. Hicks briefly 

 described the condition of the eye in some of the 

 Thysanura, pointing out that in two of the genera of 

 that order the eyes consist only of dark pigment. 

 After describing the conglomerate eye as seen in the 

 common millipede, he proceeded to give a more 

 detailed account of the eyes of spiders. He showed 

 that the disposition of the eyes in these harmless and 

 much despised little creatures, although uniformly 

 symmetrical, is extremely varied. Referring to their 

 colour and structure, he described the eyes of some 

 spiders as being of the most brilliant hues, each eye 

 a brilliant little shining hemisphere, and the tiny 

 cluster of eyes grouped in front of the head in some 

 of the Salticides sparkling and glistening like polished 

 gems, vying in colour and lustre with the emerald 

 and other precious stones. The structure of these 

 eyes, although in a somewhat rudimentary condition, 



is the same as that which exists in the higher 

 animals. The most important part of the paper was 

 that which referred to the compound eye which 

 belongs alike to the insect and crustacean. These 

 animals have two compound eyes placed one on each 

 side of the head, and each of these eyes when examined 

 under a low power is seen to be divided into vast 

 numbers of facets which in some instances are square, 

 and in others hexagonal ; the eye of the common 

 house-fly having as many as 4000 of these facets, 

 and in some beetles the number being as great as 

 25,000. Dr. Hicks proceeded to minutely describe 

 the internal structure of these compound eyes, showing 

 that they are composed of numbers of cones and rods 

 closely packed together, each rod and cone corres- 

 ponding to a facet. Dr. Hicks combated the state- 

 ment which is so frequently made in books, that each 

 of these facets represented a distinct eye, maintaining 

 that such statements were not in accordance with 

 recent microscopic investigation. After referring to 

 the manner in which the retina of the higher animals 

 is developed, he said no one could fail to be struck 

 with the similarity and agreement in the fundamental 

 plan of structure that exists between the layer of rods 

 and cones of the retina (Jacob's membrane) and the 

 arthropod eye. He showed by a series of diagrams 

 the rods and cones of the fish, the bird, the amphibian, 

 and the mammal, the similarity between these 

 structures and the rods and cones of the compound 

 eye being very striking. To his mind there was no 

 question but that the rods and cones of the vertebrate 

 eye have been originally derived from the crystaline 

 cone and nerve rod of the arthropod eye. At the 

 conclusion of the paper, a hearty vote of thanks was 

 accorded to Dr. Hicks for his valuable paper, special 

 mention being made of his admirably executed 

 diagrams. The usual conversazione terminated the 

 meeting. 



Synapta and the Frost. — The very severe 

 frost that occurred during the winters of 1877 and 

 1878 seems to have destroyed the Synapta that were 

 formerly readily procured in the mud banks oft 

 Holywood, on Co. Down side of Belfast Harbour. 

 There is great difficulty in getting good specimens 

 now, but we hope the coming summer will help to 

 restore this interesting family. I have a few duplicate 

 slides and will be glad to supply any of my former 

 correspondents who were disappointed last exchange.. 

 — William Gray, Belfast. 



Painting on Satin. — Your correspondent, S. 

 G. R., will find, if he uses white of egg instead of 

 water when painting on satin, that it will make it 

 easier for the colour to adhere. When the painting 

 is finished and dry, paint it all over with the white of 

 egg, which for both purposes should be slightly 

 liquid. — L. F. R. 



