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SCIENCE-GOSSIP. 



CONDUCTED BY J. H. COOKE, F.L S., F.G.S. 



To whom Notes, A rticles and material relating to Microscopy, 



and intended for Science-Gossip, are, in the first instance, to 



be sent, addressed "/. H. Cooke, Thomdale, Lincoln." 



To Our Readers. — When we undertook to 

 conduct the Microscopy section of Science-Gossip 

 in June last, we asked the kind co-operation of our 

 readers. We then pointed out that, to ensure the 

 success of such a department as this, something 

 more than the editorial effort is required, and we 

 asked our readers and workers to second our 

 endeavours by contributing short notes and articles 

 ■ on their own experiences and methods. We shall 

 be glad at all times to receive such contributions 

 whether illustrated or not. We also invite questions 

 and suggestions, both of which shall receive our 

 attention, and, when of general interest, we shall be 

 glad to give them place in these columns. Notes 

 on home-made apparatus, whether for the labora- 

 tory or for field work, are always interesting and 

 often valuable ; while suggestions on the time, 

 habitat and manner of collecting such material as 

 water-mites, microscopic fungi, algae, et hoc genus 

 omne would, we feel sure, be reckoned as desirable 

 information by a large section of our microscopists. 



Double Staining with Haematoxylin and 

 Safranine. — In a suggestive paper which was 

 read by Mr. F. A. Upsher Smith before the School 

 of Pharmacy Students' Association on "Quick 

 Double Staining with Haematoxylin," the methods 

 employed for showing the presence of mucilage 

 and nuclei and for contrasting the commoner kinds 

 of vegetable tissues are given in some detail. Mr. 

 Smith does not claim that the methods are original, 

 but in the course of describing these methods he 

 introduces many details of manipulation not to be 

 found in text-books and of a character such as can 

 only be known by actual practice. 



Cutting the Sections. — The sections, he insists, 

 should be as thin as possible, and the best way to 

 obtain them thus is to flood the freshly stropped 

 razor with liquid like that in which the material 

 is softened, in most cases dilute spirit. When the 

 material has been softened in a moist atmosphere 

 it is generally preferable to cut with a dry razor. 

 Holding the razor in a perfectly horizontal position, 

 draw it firmly and steadily through the material 

 held between the thumb and forefinger of the left 

 hand, and take care that nearly the entire cutting 

 surface of the razor comes in contact with the 

 material in cutting each section. Never cut more 

 than six or eight sections without stropping the 

 razor. 



The Haematoxylin Stain. — Place the sections 

 on a clean glass slide and wash with spirit of the 

 same strength as the haematoxylin stain. Cover 

 with haematoxylin stain and leave for a definite 

 time, which must vary with the thickness of the 

 section and the structure of the tissues. From one 

 to five minutes will generally be found sufficient. 



The Safranine Stain. Wash again with spirit 

 of the same strength as the haematoxylin solution. 

 This washing with spirit of a properly adjusted 

 strength must be carefully performed to ensure 

 success. Spirit washes of a different strength tend 

 to deposit dense particles of colouring matter in the 

 sections. Now cover with safranine solution and 

 allow to stand from one to thirty minutes according 

 to the material employed. Dehydrate the sections 

 by washing with fifty per cent, spirit, then with 

 absolute alcohol, and finally transfer them to clove 

 oil. If only one section is required, choose the 

 best, and manipulate it so that when soaking in 

 clove oil it takes up a position about one-third the 

 length of the slide from one end. 



Mounting the Section. — Mount permanently 

 by thoroughly drying the central part of the slide, 

 placing upon it a drop or two of Canada-balsam, 

 and quickly transfer the section with a mounted 

 needle to the balsam. Blotting-paper should be at 

 hand in order to quickly absorb the trail of clove 

 oil to prevent it diffusing into the balsam. Place 

 the coverslip in position by lowering it with the left 

 hand until the left side of it dips into the balsam ; 

 on lowering the slip rapidly by means of a mounted 

 needle held in the right hand, all bubbles of air 

 may be excluded. 



Methods of Making the Stains. — Safranine 

 solution may be made by saturating absolute 

 alcohol with safranine, and mixing with an equal 

 volume of water. For haematoxylin there are 

 many formula?. Lee's " Microtomist's Vade 

 Mecum " speaks highly of Mayer's haemalum. 

 That stain is made by dissolving a salt of haema- 

 tein and ammonia in spirit, and adding it to a large 

 volume of alum sulphate in solution. The alum 

 is supposed to be precipitated by some substance 

 present in the cellulose walls, and carries down 

 with it a certain quantity of colouring matter. 

 Lee's book gives the fullest details concerning 

 these and all other known staining reagents. 



Indian Ink in Microscopy. — Water charged 

 with Indian ink will render visible many organisms 

 that are distinguished with difficulty in water alone. 

 This method is specially to be recommended in the 

 study of many of the algae, and also in investiga- 

 tions of the digestion of the Infusoria and the 

 movements of ciliated organisms. 



Manipulative Hints. — 



(i) Xylol is the best solvent for Canada-balsam, 

 which must first be dried by artificial heat 

 in order to drive off the natural oil con- 

 tained in it. Chloroform evaporates less 

 quickly than xylol. 



(2) To cause balsam to set expose the slide to a 



temperature of about 55 C. for about six 

 hours to forty-eight hours. The longer period 

 should be preferred whenever possible. 



(3) It will be found in practice that staining sec- 



tions on a slide is quicker, cleaner and safer 

 than using a watch-glass. It is obvious that 

 a good section may easily be lost when im- 

 mersed in a watch-glass containing a com- 

 paratively deep layer of a dark stain, and 

 this danger increases with the thinness of 

 the section. 



Recent Research on Foraminifera. — The 

 current number of the " Rivista di Paleontologia " 

 contains several interesting reviews of work 

 recently done. Inter alia, we note articles by 

 Signor L. Audenino on " The Miocene Pteropods 

 of Mount Cappucini, Torino ; " by Dr. C 



