ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 505 



objects softened by means of pbloroglucin and hydrocliloric acid are after- 

 wards hardened by one of the recognized methods. As many injection 

 masses are thereby softened, Dr. Andeer recommends, if blood-vessels 

 are in question, impregnating the walls of the vessels with mineral 

 colours instead of injecting their lumen. Injection of solution of ferro 

 or ferridcyanide or sulpho-cyanide of potassium, followed by iron chloride, 

 gives excellent pictures, and the preparations thus obtained are permanent 

 and susceptible of any further treatment. 



New Method of Mounting Protozoa in Balsam.*— M. A. Certes de- 

 scribes a new method of mounting Protozoa in balsam, discovered by M. 

 Tempere : the specimens exhibited were of OpTiryoscolex and Balantidium 

 from the paunch of Ruminants. After the organisms have been fixed and 

 coloured they must be passed through alcohol of 36^, 70^, and absolute ; 

 the last ought to be renewed at least twice, and should continue to act for 

 about twenty-four hours. The absolute alcohol must then be replaced by 

 pure benzole ; a tenth of the alcohol in which the organisms are placed is 

 removed by the pipette, and replaced by the same quantity of benzole ; this 

 operation is repeated ten times, at intervals varying from ten to thirty 

 minutes. Care must be taken that the benzole mixes thoroughly ; after the 

 last addition it should be decanted, and pure benzole substituted. After 

 twenty- four or forty-eight hours in the benzole, according to the size of the 

 object, a fifth part of Canada balsam dissolved in benzole is added ; this is 

 repeated at intervals of from a quarter to half-an-hour ; and the organisms 

 may then be preserved in the tubes till wanted, or mounted at once. In 

 mounting care must be taken that each drop holds in suspension a sufficient 

 quantity of organisms. 



Microscopical Technique for small Pelagic Objects.f — Prof. J. Brun 

 gets rid of the organic detritus, &c., which accompanies the mud and ooze 

 from which Polycistina, Radiolaria, Globigerina, Foraminifera, and 

 Diatomacese are obtained, by heating the dried up mass with weak hydro- 

 chloric acid in order to remove the chalk. "When the reaction is over the 

 contents of the flask are poured on to a filter and washed. When dry the 

 deposit is treated in a flask with twice its volume of strong sulphuric acid 

 (for guanos 5-6 times this volume of acid is required). After standing 

 some time the upper three-fourths of the acid which dissolves the chitinous 

 debris is decanted off and to the thick black paste is added bichromate of 

 potash in coarse powder until it begins to turn red. By the production of 

 nascent chromic acid the last remnants of organic matter are destroyed ; the 

 residuum is then washed at first slowly and afterwards freely and by decan- 

 tation. The last washings are made with distilled water. The now whitish 

 residue is spread on large cover-glass to dry. Small sea animals may be 

 obtained alive by sweeping them off the surface water in a silk veil fastened 

 to a wire frame. The glairy mass of animals is then at once scraped into a 

 25 per cent, solution of neutral acetate of potash (solution one quart). The 

 acetate, unlike alcohol, produces no deformity, it prevents decomposition, 

 and is easily removed by washing with water. On the removal of the 

 acetate the mass is treated for several days with cold concentrated hydro- 

 chloric acid and the flask frequently agitated. The species are then 

 washed freely and calcined on the cover-glass at a dull red heat. Compact 

 masses of fossil deposit are separated by heating to about 100° and then 

 soaking in a boiling saturated solution of soda sulphate. This salt takes 

 up water as it crystallizes and consequently its dilatation renders the mass 



* Bull. Soc. Zool. Fr., xi. (1887), Proc Verb., pp. xix.-xx. 

 t Arch. Sci. Phys. et Nat., xvii. (1887) pp. 146-54. 

 1887. 2 L 



