The Philippine Journal of Science, C. Botany. 

 Vol. XIII, No. 4, July, 1918. 



SOME MICROTECHN1CAL METHODS AND DEVICES 



By Walter R. Shaw 

 (From the Department of Botany, University of the Philippines, Manila) 



FIVE TEXT FIGURES 

 CONTENTS 



1. Ocular micrometers used as stage micrometers. 



2. The square-ruled micrometer used as a position indicator. 



3. The square-ruled micrometer for drawing to scale. 



4. Capillary glass rods for cover-glass supports. 



5. Autographic records on micrographic negatives. 



6. A method of recording magnification on micrographic negatives. 



7. Concentration of glycerin hastened by the vacuum pump. 



8. A method for making sealed glycerin mounts. 



9. The Osterhout mounting method adapted to Volvocaceae. 



10. A plankton net for larger organisms. 



11. Washing devices for small objects. 



12. Methods of estimating the number of cells in. spheroidal surfaces. 



During several years of teaching botany and pharmacognosy, 

 and collecting and preparing material for a study of the Volvoca- 

 ceae of the vicinity of Manila, it has been found expedient to 

 employ modifications of the methods laid down in the various 

 laboratory handbooks. For the most part these modifications, 

 made to meet requirements of the work in hand and local con- 

 ditions, have originated in suggestions obtained during many 

 years from many sources which it would now be difficult, if 

 not impossible, to trace. The methods and devices here pre- 

 sented have served useful purposes for the writer and his stud- 

 ents in the past and are here published that they may be available 

 for others in the future. 



OCULAR MICROMETERS USED AS STAGE MICROMETERS 



In an instruction laboratory in which each compound micro- 

 scope is furnished with a linear and a square-ruled micrometer 

 disk, each of these scales may be used as a stage micrometer 

 for determining the value of the intervals of the other used 

 as an ocular micrometer. The disk to serve as the stage micro- 

 meter is easily affixed to a clean slide with a capillary film of 

 water. By this means I am enabled to give simultaneously to 

 all the students of a class exercises in the determination of the 

 micrometer scale values without the expense of supplying a 

 stage micrometer for each student. 



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