872 Special Procedures II (chap. 23) 



2. Cocaine can be used for ciliates, rotifers, bryozoa, hydra, some worms and 

 nudibranchs. A 1% aqueous solution is added to the water in proportions 

 of about 1.0 ml. to 100.0 ml. of the water containing the animals. Eucain 

 hydrochloride can be used in the same manner. Check for contraction 

 and fix. 



3. Menthol. Sprinkle on the water surface and leave overnight. Good for 

 difficult to narcotize sessile marine animals, coelenterates, some bryozoa, 

 hydroids, also flukes. It is more efficient when combined with chloral 

 hydrate in proportions of 45.0 gm. menthol and 55.0 gm. chloral hydrate. 

 Grind together in a mortar with a little water. Drop on surface of the 

 water. Fix animals when they no longer contract. Large marine forms 

 probably will require overnight treatment. Chloral hydrate can be used 

 alone, sprinkled on water surface for annelids, molluscs, tunicates, bry- 

 ozoans and turbellaria. 



4. Chloretone. A 0.33 to 1% solution can be used, but it is slow acting. 



5. Chloroform can be dropped on the water surface for many aquatic 

 forms, and is used in special bottles for insects and arachnids (see below). 



5. Ether and alcohol can be used by dropping on the water, or alcohol 

 can be added gradually to the water by a tube controlled with a screw 

 clamp until the proportion of alcohol to water is approximately 10%. 

 It is particularly good for fresh water forms and earthworms. Ether 

 can be used like chloroform for insects. 



7. Asphyxiation. Boil water to remove the air and seal it in a jar. Particu- 

 larly good for gastropods (snails); place them in the boiled water after 

 it has cooled. 



8. Cold. Partially freeze organisms in salt and ice mixture or in freezing 

 compartment of refrigerator, or in ice water until they are relaxed. 

 Good for tapeworms. Transfer to lukewarm water and then fix. 



Tips on special handling 



PORIFERA. 



Small forms can be dropped directly into osmic-mercuric chloride 

 (water, 250.0 ml.; osmic acid, 2.5 gm.; mercuric chloride, 9.0 gm.). Large 

 forms fix better in alcoholic sublimate (Gilson; Carnoy). 



Calcareous sponges can be decalcified in 70-80% alcohol plus 3% of 

 hydrochloric or nitric acid. Silicioiis ones can be desilicified in 80% 

 alcohol plus 5% hydrofluoric acid added gradually. Perform the latter 

 in a glass dish coated inside with paraffin. After a few hours, transfer to 

 80% alcohol. Do not breathe hydrofluoric acid fumes. If sectioning 

 sponges, small spicules will section easily without disilicification. 



