1S4 



IIARDWICKE'S SCIENCE-GOSSIP. 



were no less than seven full-sized Natterjacks. The 

 burrows were just sufficiently wide and deep to 

 accommodate the reptiles. The creatures had un- 

 doubtedly made these burrows themselves, and here 

 they were quietly crouching. On the roof of their 

 dwelling being taken off, they began moving directly, 

 some insinuating themselves under the reversed 

 stone, and others moving off altogether. Raising 

 the adjoining stone rather nervously, I was again 

 astonished ; for, behold, under that crouched seven 

 other Natterjacks ; but these, instead of being 

 adults, were exact counterparts of those I had found 

 wandering among the grass. These little Natter- 

 jacks had also hollowed out winding burrows, suited 

 to their size, under the stone, and, like the larger 

 ones, immediately dispersed as soon as the latter 

 was raised. A sharp thunder-shower now coming 

 on put a sudden stop to my investigations, com- 

 pelling me to leave the haunts of Natterjacks for 

 those of men. 

 Stand-lake, Oxon. W. II. Warner. 



MICROSCOPY. 



Polarizing Salts.— In Dr. Carpenter's " Micro- 

 scope and its Revelations," 5th edition, 1S75, p. 812, 

 you may find a long list of salts, &c, particularly 

 fit for polarizing objects. I have already tried a 

 great many of them, but all do not answer as I 

 should desire, even after many experiments, and 

 some are not polarizing at all. Without doubt, the 

 error is on my side, for want of sufficient knowledge 

 about chemistry. I have thought there was, per- 

 baps, a more general interest amongst professors of 

 micro-polarizing apparatus, as I am writing to know 

 bow to obtain really fine preparations from the said 

 salts, double salts, &c. Some hints are to be found 

 in several manuals, but they are very much dispersed. 

 Is it not possible that in your periodical an article 

 could be published about this subject from the hand 

 of one or more experienced chemical microscopists, 

 such as Mr. Kitton and others, according to the list 

 of Dr. Carpenter, and fully describing the modus 

 operandi for the several chemicals ; viz., the best 

 treatment exclusively for the polariscope ? I think 

 this would be useful, not only for beauty's sake, 

 but, perhaps, in order also to promote a taste for 

 chemistry among youth. I shall be glad to see in 

 some following " monthly " that my idea has had 

 your attention.—/. Kinker, Amsterdam. 



The Preparation of the Diatomace.e.— J. 

 D. Moller (the well-known preparer of the Typen 

 and Proben Platte) has announced that he will pub- 

 lish a small work on the complete preparation of the 

 Diatomaceas (Die Pri'tparation der Diatomaccen in 

 ihrem ganzem Umfange). Its contents will be as 

 under:—!. Collecting. 2. Cleaning:— (a) living; 



(b) dead forms in mud ; (c) fossil forms. 3. The 

 separation of the different species. 4. The prepara- 

 tion and mounting : — (a) in, the usual manner {mixed 

 on spread slides); (b) as selected or arranged; (c) as 

 Typen and Proben Platte. The work will be pub- 

 lished by subscription at the following prices : — 

 German edition, 30 marks ; Englisb edition, 32s. ; 

 French edition, -10 francs. In the event of a suffi- 

 cient number of subscribers being obtained to remu- 

 nerate the author for making public bis method of 

 preparing and mounting the Diatomacea?, every 

 subscriber will receive his copy in the beginning of 

 1S70 on remitting the amount of subscription to the 

 author— J. D. Muller, Wedel (Holstein) ; or to 

 C. Baker, 244, High Holborn, W.C. ; E. Wheeler, 

 4S, Tollington-road, N.; R, & J. Beck, Coruhill, 

 E.C. Orders must be sent in not later than Sept., 

 1875 ; in October the subscribers will be informed 

 whether the book will be published or not. — F. K. 



Anatomy of Ampiiioxus. — A paper on this 

 subject has been read at the Linnean Society by 

 Prof. Ray Lankester, E.R.S. The author described 

 the anatomy of A. lanceolatus as worked out in a 

 series of sections made from numerous specimens 

 collected by him at Naples. In opposition to Stieda, 

 the truly perforate structure of the pharynx was 

 asserted. A true body cavity or coelon, distinct 

 from the atrial chamber, was described, and it was 

 shown to expand and attain a large development in 

 the post atrioporal region of the body. A pair of 

 pigmented canals were described, apparently repre- 

 senting the vertebrate renal organ in a degenerate 

 cr else a rudimentary condition. Johannes Midler's 

 pores of the lateral canals were shown to be hyoid 

 slits leading into the pharynx. The attachment of 

 the pharyngeal bars to the wall of the atrium by a 

 series of pharyngo-pleural septa was minutely de- 

 scribed. It was further shown that the marginal 

 ridges of the ventral surface (metapleura) are hollow, 

 containing a lymph-space, and that they, as well as 

 the plates of the ventral integuments, disappear 

 when the atrial chamber is largely distended with 

 the sexual products. Drawings by Mr. W. J. 

 Eanning, of Exeter College, were exhibited in illus- 

 tration of the above statements. 



The Compound Microscope in the Examina- 

 tion of Patients.— The Monthly Microscopical 

 Journal states that Dr. H. G. Piffard has devised a 

 simple contrivance, by means of which the binocular 

 microscope can be employed in the ordinary " out- 

 patients' room," for the examination of the skin of 

 patients suffering from skin diseases. Dr. Piflard 

 says: — "The objectives which I employ are a G", 

 2", and 1" of Grunow, and a 4" and I" of Ross. The 

 I" is made with taper front, specially constructed 

 for use with reflected light. The advantages of this 

 arrangement over the single lens are enlargement 



