LABORATOHY WORK WITH ANTHEAX ANIMALS. 293 



the water-bath until everything dissolves, and the solution 

 has a clear, deep bright-red color. 



The carbolic fuchsin prepared as above will keep for a consid- 

 erable length, of time. It should always be warmed on the iron-plate 

 in order to bring the constituents into solution. Eventually, an 

 insoluble deposit forms and the solution becomes more transparent, 

 weaker, and hence stains less energetically than in the beginning. 

 Instead of preparing a large amount of carbolic fuchsin it is better 

 to dissolve the constituents separately and to bring these together in 

 small quantity, whenever desired. 



For this purpose 8 g. of fuchsin are dissolved by heat in 120 c.c. of 

 absolute alcohol. A deposit may form on cooling, hence before meas- 

 uring out the liquid it should be warmed till complete solution results. 

 15 c.c. of this solution contain 1 g. of fuchsin. The addition of 7. 5 

 c.c. of the liquid to 50 c.c. of 5 per cent, carbolic acid will, on warm- 

 ing, give an excellent Ziehl solution. Tubercle bacilli which will not 

 stain with old carbolic fuchsin will promptly react with a fresh solu- 

 tion prepared in the manner described. 



The following summary will be of assistance when 

 staining spores: 



Cover-glass preparation. 

 Dry in air. 



Simple: Double: 



Pass 12 times or less through Pass once through flame. 



flame. Carbolic fuchsin (hot 2 to 5 min.). 



Carbolic fuchsin (hot i min.). Wash and examine in water. 



Wash in water. Wash in dilute alcohol. 



Examine in water. Wash and examine in water. 



Dry in air. Contrast color (methylene blue, 



Mount in balsam. i - i min. ). 



Wash and examine in water. 



Dry in air. 



Mount in balsam. 



Phagocytes. — According to Metchnikoff's cellular theory 

 of immunity, the white blood cell is endowed with the 

 power of taking into itself, and ultimately destroying, the 

 invading organism. Phagocytic action can be readily 

 demonstrated in frogs inoculated with anthrax. For this 



