HARDWICKE'S SCIENCE-GOSSIP. 



2 5 



GRAPHIC MICROSCOPY. 



By E. T. D, 



No. 14. — Toe of Mouse, Injected. 



*^&^£ HIS sub J ect ex ' 

 plains itself, 



revealing a distri- 

 bution of blood 

 vessels, in a trans- 

 parent section of 

 the toe of a mouse. 

 The skill required 

 to success fully 

 inject the vessels, 

 and afterwards 

 procure so delicate 

 a scission, is es- 

 sentially the pro- 

 vince of the pro- 

 fessional preparer ; 

 but, the object is 

 sufficiently "popu- 

 lar," to be pur- 

 chasable, and is 

 found in most col- 

 lections of microscopic objects. Although not 

 approaching the stern requirements of the biologist 

 or anatomical student, as revealing disentanglement 

 of delicate tissues, or isolation of determinate 

 structure, it is eminently a valuable educational or 

 class preparation, as exhibiting conditions of distinct 

 parts seldom found, in one view so intimately or 

 compactly associated. The drawing was made from 

 a "happy" cut, just cleaving, without injuring or 

 disturbing, the tarsal bones, showing them in perfect 

 integrity, surrounded by minute blood vessels 

 spreading from the digital artery, and continuing to 

 the capillary loops terminating in the papillae of the 

 thick, but highly sensitive, and vascular* epidermic 

 cushion under the surface of the claw, the matrix of 

 which is seen, penetrated with minute blood vessels. 

 Elegant and instructive as this preparation may be, as 

 a microscopic exhibit, it is as nothing compared to 

 such a condition in a living state, with the blood 

 coursing through the vessels ; the web of a frog's 

 foot, the branchire and transparent parts of a tadpole, 

 No. 242. — February 1885. 



the fins and tail of minnows, many of the larva; of 

 water insects, and, par excellence, the yolk bag of 

 freshly hatched fish, may be, by well-known methods, 

 arranged, and disclose on the stage of the microscope, 

 exhibitions of energetic life, in the circulation of the 

 blood, of the deepest and most impressionable 

 significance. 



Addendum. Eyla'is cxtendens : In the January 

 article on this subject, it was stated that the comely 

 rotundity of the Ilydrachnas rendered them difficult to 

 preserve, as permanent specimens for the cabinet, 

 except at the sacrifice of their shapeliness, the 

 dilemma being to find a medium of just the density 

 needed to preserve the integuments from wrinkling 

 or collapse. The writer has since received, through 

 the courtesy of Mr. Henry Francis, the President of 

 the Bristol Microscopical Society, a specimen en 

 permajience, mounted three years ago : enclosed in 

 a deep circular cell. The medium Mr. Francis used 

 is a mixture of eight parts of distilled water (just 

 tainted with carbolic acid), to one part of pure 

 glycerine ; under severe examination, although a 

 little " off colour," its characteristic plumpness is 

 perfectly intact, and such important features as the 

 curious ocelli, the palpi, the parts about the mouth 

 and the genital plates, are so well preserved and 

 displayed, as to bear scrutiny under the highest 

 reaching powers. 



Crouch End. 



Bats. — A correspondent in the December issue 

 tells us he has often seen bats flying about the streets 

 of Maidstone in mild weather during the autumn and 

 winter months. This reminds me of what I saw in 

 Paris on the first Sunday in January 1S71. During 

 the service in the church of St. Roch, I saw several 

 bats flying about in the church between three and 

 four in the afternoon. Afterwards in the evening 

 twilight of the same day, I saw a good number flit 

 about in a very lively fashion on the banks of the 

 Seine.— H. M.,Birkdale. 



c 



