152 



SCIENCE-GOSSIP. 



Globigerina Limestones. — The comparative 

 study of recent and fossil deep-sea deposits is one 

 of the most interesting subjects that a microscopist 

 can take up. Of the fossil deposits, the chalk is a 

 familiar example. The less-known limestones of 

 Miocene age, which are found in Italy, Malta and 

 the Vienna Basin are, however, the best for 

 purposes of comparison. The accompanying 

 figures illustrate the composition of some of these 

 old deep-sea beds. Fig. i shows the limestone to 

 be made up of the shells of pelagic Globigerinae 

 and their broken-down remains. Mixed up with 

 these are a few Tritncatnlina, Pulvinulina, and 

 Rotalia shells, Ostracode valves, Echinoderm 

 species, and a few Coccoliths, Coccospheres and 

 Rhabdoliths. Very frequently the Globigerina 

 shells make up eighty or ninety per cent, of the 

 whole rock, hence the name given to the limestones. 

 Fig. 2 represents a micro-section of the rock that 

 overlies the Globigerina limestones in the Maltese 

 area. It is a typical Greensand, and its constitu- 

 ents indicate a considerable shallowing of the sea 



Staining Tubercle Bacillus. — According to 

 Dr. G. Sims Woodhead, the following is one of the 

 best methods of staining the tubercle bacillus. The 

 small, yellow, caseous-looking points from a sputum 

 rich in the bacilli are spread out by pressure 

 between two cover-glasses, so that a fairly thin film 

 remains on each when they are carefully slipped one 

 over the other until they come apart. Thoroughly 

 dry the covers, protecting them from dust, pass 

 rapidly three times through the flame of a spirit 

 lamp, care being taken not to scorch the film, 

 then float film face downwards on the staining 

 solution, which has previously been filtered into 

 a watch-glass. The stain should consist of satur- 

 ated alcoholic solution of basic fuchsin, one part ; 

 absolute alcohol, ten parts ; carbolic acid solution 

 (five per cent.), ten parts. Leave the preparations 

 in the watch-glass for twelve to twenty-four hours, 

 unless time is an object. In the latter case heat 

 the fluid gently until vapour is given off, then drop 

 the films on the surface and leave them for from 

 three to five minutes only. Next transfer the 





Fig. I.— Globigerina Limestone. 





Fig. 2. — Greensand. 



bed in the Central Mediterranean. Its foramini- 

 feral contents are as follow : Globigerina, OrhiUna 

 Rotalia, Pulvinulina, Truncatulina, Texhuaria, Planar- 

 bulina, calcareous algae, mollusc shells. Polyzoa 

 Echini spines, Ostracode valves and Glauconite 

 Besides these the Greensands were found to con 

 tain the following mineral particles : glauconite 

 felspars, quartz, augite, hornblende, magnetite, 

 zircon and tourmaline ; all of which go to prove 

 the proximity of a shore-line at the time of the 

 deposition of the beds. 



Amplifier. — Thirty years ago Dr. Woodward, 

 of the Army Medical Museum, was deeply in- 

 terested in perfecting the art of photo-microscopy. 

 The device of introducing into the body of the 

 microscope an amplifier was so successfully carried 

 out that he was enabled to obtain a greater and 

 more accurate amplification or magnification of 

 the object with a Wales one-sixth than was possible 

 with the Powell and Leland one-fiftieth. A micro- 

 photograph of a frustule of the diatom Pleurosigma 

 angulatuiu had its markings so resolved by the one- 

 sixth plus the amplifier, that they were shown to 

 be hemispherical bosses of silica rather than 

 hexagons, as the one-fiftieth and all other lenses 

 then known made them appear. The result was 

 owing to the superior resolving power of the one- 

 sixth plus the amplifier. 



cox'ers to an aqueous solution of sulphuric acid 

 (twenty-five per cent.) and when decolourization is 

 complete thoroughly rinse in slightly alkaline water 

 and counter-strain in an aqueous solution of methy- 

 lene blue. Finally wash in water, carefully dry 

 and mount in Canada-balsam The bacilli should 

 stand out as bright red rods on a blue background 

 of cells. 



Paraffin Imbedding Dish. — In the "Journal 

 of Applied Microscopy," Mr. E. Mead Wilcox 

 gives the following simple method of making a 

 paraffin imbedding dish : A Stender dish of the 

 desired diameter, depending on the amount of 

 material to be imbedded, is inverted, and a piece 

 of firm paper is wound lightly about it, so that the 

 edge of the paper projects one centimeter or more 

 above the glass bottom. The free ends of the 

 paper are allowed to overlap and are held together 

 by a piece of gummed paper placed on the outside. 

 The glass bottom of the Stender dish and the 

 paper constitute the imbedding dish. The glass 

 bottom of the dish is coated with glj-cerine so 

 that the parafiin block can readily be removed. 

 When the paraffin is sufiiciently cooled, invert 

 the dish and allow water to run into the Stender 

 dish, thereby cooling quickly the paraffin on the 

 side next the glass. The paper can then be torn 

 away. 



