78 Modern Microscopy. 



Staining Process. (1) Place the section in distilled 

 water to wash away the alcohol, then place a little of the 

 carmine in a watch-glass, and immerse the section for from 

 three to five minutes. 



(2) Wash the section in methylated spirit. 



(3) Take of methylated spirit 5 parts, and of hydrochloric 

 acid 1 part, and mix them well together. A quantity of 

 this acid solution may be made up and be kept ready for 

 use at any time. 



Immerse the section in the above, and leave it to soak for 

 about five to ten minutes, or, if overstained, until the desired 

 tint is obtained. Sections of skin and scalp may be left 

 until all colour is removed from the fibrous tissues ; the 

 glands, hair follicles, and Malpighian layer will then stand 

 out clearly. 



(4) Wash the section well in methylated spirit to remove 

 all traces of the acid, then transfer to some perfectly clean 

 and strong methylated spirit for from ten to fifteen minutes 

 to dehydrate. 



(5) Place some oil of cloves in a watch-glass, take the 

 section from the spirit on a lifter, and carefully float it on 

 to the surface of the oil, in which it must remain for about 

 five minutes. This process is called clearing ; the object of it 

 is to remove the alcohol and to prepare the section for the 

 balsam. 



(6) Transfer the section to some filtered turpentine to 

 wash away the oil of cloves, and mount it in Canada balsam. 

 Sections may be mounted in C. balsam direct from the 

 oil of cloves, but it is better to wash in turpentine first, be- 

 cause if much oil is mixed with the balsam it will not dry ; 

 the oil also has a tendency to cause the balsam to turn a 

 dark-yellow colour. 



Logwood or Hsematoxylin. Haematoxylin 30 grains, 

 absolute alcohol 3J ounces, distilled water 3J ounces, 

 glycerine 3J ounces, and ammonia alum 30 grains. Dis- 

 solve the haematoxylin in the alcohol and the alum in the 

 water ; mix the two solutions together, and add the glycerine 



