376 SUMMARY OF CURRENT RESEARCHES RELATING TO 



such as nuclei, muscular fibres and glands. The plankton, either salt or 

 fresh-water, is allowed to remain for 24 hours in the quinone solution, 

 which must be freshly prepared as it decomposes under the influence of 

 air, water and light. After an immersion of 24 hours the quinone is 

 replaced by 70 p.c. alcohol. When it is desired to mount the animals 

 in toto, they are passed through upgraded to absolute alcohol, to which 

 last is gradually added either oil of bergamot or oil of cloves ; after a 

 stay of some hours in the pure oil, the animals are mounted in balsam. 

 For histological examination the quinone may be combined with per- 

 chloride of mercury, picric and acetic acids. As the reaction of quinone 

 is neutral it does not interfere with staining reactions, and, indeed, may 

 act as a mordant. 



Studying Metamorphosis of Muscidse.* — C. Perez in his research 

 used Calliphora erythrocephala ; specimens at every stage of development 

 were examined, and the methods of fixation and staining were very 

 varied. The chief fixatives were acetic-acid-sublimate and the picro- 

 formalin of Bruin. As a nuclear stain Mayer's hasrnaluni was mostly 

 used, the plasma being contrast stained with eosin and aurantia. Often 

 the iron-hiemotoxylin method was substituted for the haemalum. Occa- 

 sionally the preparations were contrast stained with carmine hydro- 

 chloride, and then differentiated with picro-indigo-carmine. For osmic 

 acid fixation, Borrel's formula was adopted (osmic acid 2, platinum 

 chloride 2, chromic acid 3, glacial acetic acid 20, water 350). After 

 24 hours the preparations were washed in running water. The sections 

 were contrast stained with 1 p.c. magenta red, and afterwards for 10 to 

 20 minutes in picro-indigo-carmine (saturated aqueous solution of picric 

 acid 1 vol., saturated aqueous solution of indigo-carmine 2 vols.). The 

 preparations were differentiated with absolute alcohol and oil of cloves. 

 The author points out that osmic acid penetrates feebly, and therefore 

 this reagent should not be adopted as the chief fixative. 



Studying the Neurofibrils in Lumbricus.f — J. Kowalski finds that 

 in order to successfully demonstrate the neurofibrils in Lumbricus, the 

 silver impregnation should be effected by means of an acid medium, 

 and the fluid used by him which gave the best results was composed of 

 formol 25 c.cm., glacial acetic acid 5 c.cm., distilled water 100 c.cm. 



Two other fixatives recommended by Bouin were as follows : — 1. 

 Distilled water 100 c.cm., formol 25 c.cm., glacial acetic acid 5 c.cm., 

 ammonia ■ 5 c.cm. 2. Alcohol 94 p.c. 100 c.cm., formol 75 c.cm., glacial 

 acetic acid 5 c.cm., ammonia ' 5 c.cm. 



(3) Cutting:, including- Imbedding- and Microtomes. 



Studying Eye of Pecten.J— W. J. Dakin carried out his investi- 

 gations on the eye of Pecten by means of paraffin and paraffin-celloidin 

 sections, by maceration preparations, and by teased out specimens of 

 fixed material. Maceration was found to give important results, and it 

 was noted that different reagents were requisite for maceration and fixa- 

 tion purposes. The best fixatives were Zenker's fluid and Carnoy's 



* Archiv Zool. Exper. et Gen.,xliv. (1910) pp. 1-274 (16 pis. and 162 text figs.). 

 t La Cellule, xxv. (1909) pp. 291-347 (4 pis.). 

 t Quart. Journ. Micr. Sci., lv. (1910) pp. 53-6. 



