EnibeddiJig Cellular Contents of Body Fluids 39 



2. Mount block in a small hole dug in a square of paraffin and blend two 



together with a warm needle or spatula. 

 Farnsivorth [1956) transfers minute pieces with a pipette to a piece of lens 

 paper lying on a blotter. The latter absorbs the fluid, then the lens paper 

 bearing the tissue is laid flat on the surface of melted paraffin. She embeds 

 in depression slides wiped with glycerine. 



Arnold (1932) concentrates small organisms in agar and carries through with 

 the usual processes. 



[See also DeR^ecchio et al. (1959); DeWitt et al (1957); McCormick 

 (1959B); Seal (1956); Taft and Arizaga-Cruz (I960).] 



Dehydration and Clearing Combinations 



Dioxane Method. 



Any procedure which shortens the processing time for embedding has 

 considerable merit and finds favor amons: technicians. In 1931 an article 

 appeared concerning a reagent, which dehydrated as well as cleared in a 

 minimum of steps. Graupner and Weissherger {1931) proposed the use 

 of dioxane (diethyl dioxide), miscible with water, alcohol, hydrocarbons 

 and paraffin. It seemed to eliminate soine shrinkage and hardening, and 

 was a relati\ely inexpensive method because fewer solutions Avere re- 

 quired. Dioxane itself, however, is far more costly than alcohol. 



Some technicians claim that it has other disadvantages. Conn (1939) 

 cautioned that dioxane was ciuTiulatively toxic and that it should not 

 be used by any person with liver or kidney trouble. Navasqiiez (1935) 

 reported that dioxane toxicity for animals w^as relatively low, that there 

 A\as no accinnulative effect, and that a tolerance would develop. Such 

 cases as w'ere noted in man came after a period of heavy exposure to the 

 vapor. It ^vas acute, not a chronic, poisoning. Fairly et al. (1936) said 

 there is some evidence that toxic effects are due to oxidation products: 

 oxalic acid and diglycolic acid, which are considered to be nontoxic to 

 man. Perhaps it is Avell to be caiuiotis; use dioxane only in a well- 

 ventilated room and a^vay from the nose. Avoid unnecessary soaking of 

 hands in it. Keep dioxane containers tightly closed at all times. 



Because of its low tolerance to ^vater, carelessness in the use of 

 dioxane can lead to trouble. If the tissue shrinks (it may shrink as much 

 as 40-50%) during infiltration with paraffin, Avater is present. The 

 author has seen this happen frecjuently for beginning students. Stowell 

 {19-il) reported 35% shrinkage with dioxane and further condemned it, 

 saying that some brands already contain at least 10% water and other 

 impurities even before use. Cloudiness appears at 1% water content. 



