368 SUMMARY OF CUEREXT RESEARCHES RELATING TO 



hours. 4. Immerse in up graded alcohols (25, 45, 75 and 92 p.c). 

 For this stage it is advisable to place the insect between two slides, 

 arranging the various in suitable position, fastening the slides together 

 by means of rubber bands. 5. Cedarwood oil. 6. Thin balsam in 

 benzol. 7. Thicker balsam in benzol. 8. Mount in balsam under 

 oblong cover. 



Terpineol.* — H. Womersley finds in terpineol a medium for clearing 

 microscopical sections which will replace all other oils at present in use. 

 Its virtues are that it does not dissolve celloidiu, it has a perfect clearing 

 action, its refractive index is I'id, it does not dissolve aniline pigments, 

 it will dissolve paraffin on warming to about 20° C, and so will serve 

 for infiltrating specimens. Terpineol is manufactured synthetically 

 from oil of turpentine. Another merit is that it is fairly cheap. 



f6) Miscellaneous.! 



New Apparatus for Wax-plate Reconstruction Work.t — L, Neu- 

 meyer descriljes two new pieces of apparatus for this type of work. The 

 first of these is an electrically-heated roller, the temperature of which is 

 capable of accurate adjustment. Further, an account is given of a 

 sliding bar, automatically regulated, by means of which the thickness 

 of the plate is determined. The instruments are made by the firm of 

 C Koch and N. Iblherr, of Munich. 



New Method of Counting Blood Platelets. J — J. H. Wright and 

 R, Kinnicutt have devised the following method for counting blood 

 platelets : — The blood is mixed with a diluting fluid in the proportion of 



1 to 100 by means of the pipette used for counting red corpuscles, and 

 the counting is done in an ordinary blood-counting chamber with a 

 high-power dry objective. 



In order to render the platelets more clearly visible, the extra thin 

 slips with central excavation (No. 146 Zeiss) are used. The diluting 

 fluid consists of an aqueous solution of brilliant cresyl-blue (1-300), 



2 parts, and aqueous solution of potassium-cyanide (1-1400), 3 parts. 

 These two solutions are kept separate and mixed and filtered immediately 

 before use. The pipette, as in blood counting, must be well rolled and 

 shaken before withdrawing a portion for counting. 



After the counting chamber is filled it is left to rest for about 15 

 minutes to let the platelets settle. The platelets appear as sharply out- 

 lined, round, oval, or elongated lilac-coloured bodies. The red cor- 

 puscles are decolourized, and the nuclei of the whites are dark blue. 

 The average count for normal individuals came out at about 275,000. 



* Micrologist, i. (1912) pp. 115-6. 



t Zeitschr. wiss. Mikrosk., xxviii. (1912) pp. 291-300. 



X Publications IMassachusetts Gen. Hosp., iii. (1911) pp. 505-11. 



