APPENDIX 



451 



To Prepare Tape-worms. Wash in salt solution. Wrap around a piece of glass 

 as a glass slide and fix in salt solution containing 2 to 5% of formalin. Then keep 

 the preparation permanently in 70% alcohol. If preferred, the specimen may be 

 run through alcohols and xylol and mounted in balsam. 



Larvae. Mosquito larvae may either be prepared as for small round worms or 

 they may be dropped into 70% alcohol at 6oC. and then passed through alcohols 

 and cleared in xylol and mounted in balsam. Flukes and insects may require treat- 

 ment with hot (60 to 7oC.) solution of 10 to 20% sodium hydrate solution. Then 

 wash thoroughly in water and subsequently pass through alcohols to xylol and mount 

 in balsam. Clove oil or cedar oil clears more slowly, but makes specimens less brit- 

 tle than does xylol. Another satisfactory method is to drop insects or larvae into 

 acetone at 6oC. and after being in this from one to twelve hours to clear in xylol 

 or clove oil and mount in balsam. 



Nematodes. Looss has a method of first washing a small nematode or delicate 

 fluke in salt solution. Then pouring this first salt solution out of the test-tube in 

 which the washing was carried out, to add fresh salt solution, and then an equal 

 amount of saturated aqueous solution of bichloride of mercury. The shaking is 

 easily carried on in the test-tube. After washing in water the worm is passed 

 through alcohols, one strength of which should contain iodine. Clear in xylol and 

 mount in balsam. 



An excellent method is that of Langeron. 



After washing in salt solution fix for a few hours in 5% formalin. Then transfer 

 to lactophenol which has been diluted with an equal amount of water. Allow to 

 remain in this solution for several hours and then transfer to pure lactophenol in 

 which fluid the specimens are to be mounted. Ring with paraffin or with gold size. 

 (To make lactophenol take 2 parts of glycerine and i part each of distilled water, 

 crystallized carbolic acid and lactic acid.) 



A quick method of preparing small nematodes for examination is to fix them for 

 from two to twelve hours in 5 to 10% formalin, this being heated at 6oC. at the 

 time the worms are dropped into it. Then transfer to the following solution: 



Glucose syrup (glucose, 48; water, 52), 100 c.c. 



Methyl alcohol, 20 c.c. 



Glycerine, 10 c.c. 

 Camphor, q.s. (a small lump for preservation). 



They may be mounted directly in this and the cover-slip ringed with about 6oC, 

 paraffin, followed with gold size. 



Preparations so cleared and mounted in glycerine jelly should also be ringed with 

 paraffin or some cement. 



Flukes, cestodes, and nematodes are best stained with carmine. The following 

 is a good formula. 



Dissolve, by boiling, 4 grams carmine in 30 drops HC1 and 15 c.c. water. Then 

 add 95 c.c. of 85% alcohol and filter while hot. Neutralize with ammonia until 

 precipitate begins to form. Then filter cold. 



i. Stain parasites taken from 70% alcohol for five to 'twenty minutes. 2. Dif- 

 ferentiate in 3% hydrochloric acid. 3. Pass through alcohols to xylol and mount in 

 balsam. 



