BLOOD-SERUM 



169 



6. Heat tubes containing serum to 56 C. in a water- 

 bath for half an hour on each of two successive days. 



7. On the third day, heat the tubes, in a sloping 

 position, in a serum inspissator to about 72 C. (A 

 coagulum is formed at this temperature which is fairly 

 transparent; above 72 C., a thick turbid coagulum is 

 formed.) 



FIG. 109. Blood-serum jar with wicker basket for transport. 



The serum inspissator (Fig. no) in its simplest form 

 is a double-walled rectangular copper box, closed in by 

 a loose glass lid, and cased in felt or asbestos the 

 space between the walls is filled with water. The 

 inspissator is supported on adjustable legs so that the 

 serum may be solidified at any desired " slant," and 

 is heated from below by a Bunsen burner controlled by 

 a thermoregulator. The more elaborate forms resemble 

 the hot-air oven (Fig. 26) in shape and are provided 

 with adjustable shelves so that any desired obliquity 

 of the serum slope can be obtained. 



8. Place the tubes in the incubator at 37 C. for 



