30 Animal Micrology 



MEMORANDA 



1. Tissues Are Preserved in Alcohol of from 70 to 85 per cent, strength, 

 but if they are to remain several months it is better to preserve them in 

 a mixture of equal parts of glycerin, distilled water, and 95 per cent, 

 alcohol. 



2. Hardening. Read carefully the remarks on hardening in chap. ii. 



3. Tissues Should Not Be Left in the Fixing Agent longer, ordinarily, 

 than is necessary to get results. Some, however, require a long time to 

 bring out the optical differences of their elements. Experience alone 

 can teach the time required in a given case. Such a reagent as formalin 

 kills, fixes, hardens, and preserves, all at the same time. 



4. For Transferring Small Objects through reagents the method of 

 Walton is an excellent one. For the several reagents, he uses shell 

 vials which measure about 10 cm. in height by 3 cm. in diameter. 

 Through the center of a flat cork which fits the vials, a hole is made and 

 a glass tube (about 9 cm. by 1.5 cm.) is inserted so that its lower end dips 

 well into the reagents in the vials. The lower end of the tube is closed 

 with fine-meshed cloth and the objects are placed within the tube. To 

 transfer the objects one simply removes the cork bearing the tube, and 

 inserts it in the vial containing the desired reagent. The upper end of 

 the tube may be closed with a cork of the proper size. To avoid disturb- 

 ance from changes in air pressure a small hole should be bored in the 

 side of the tube just below the lower level of the larger cork. The vials 

 are supported as indicated in memorandum 5. 



5. Shell Vials, Small Bottles, etc., when in use are best supported 

 in shallow auger holes of proper size in thick blocks of wood. 



6. Material Which Is To Be Kept Indefinitely should be put in tightly 

 stoppered vials in a place away from strong light. It is best to pack the 

 vials in a museum jar on cotton and then seal the jar securely to prevent 

 evaporation. Material is even more secure if the museum jar is partly 

 filled with alcohol; in such a case each small vial should have a label of 

 the contents placed within it. 



Another way to prevent evaporation from vials or bottles is to "cap" 

 them with a suitable varnish (see 7). 



7. To Seal Bottles and Preparation Jars (''bottle-capping") dip the 

 stopper and part of the neck m collodion varnish made as follows: 



Pyroxylin 1 oz. 



Ether . . . . 6 oz. 



Alcohol 8 oz. 



When the pyroxylin has completely dissolved add 2.5 drams of camphor. 

 (From Pharmaceutical Era, Vol. XXX, p. 528.) 



