38 



ESSENTIALS OF BACTERIOLOGY. 



Staining*. All the various solutions should be in readiness, 

 best placed in the little dishes in the order in which they are to 

 be used, as a short delay in one of the steps may spoil the speci- 

 men. 



A very useful instrument for transferring the delicate sections 

 from one solution to another is a little metal spatula, the blade 

 being flexible. 



A still better plan, especially when the tissue is "crumbling," 

 is to carry out the whole procedure on the glass-slide. 



FIG. 13. 



Section Microtome. 



General Principles. The section is transferred from the alco- 

 hol in which it has been kept into water, which removes the 

 excess of alcohol, from here into 



Dish I, containing the stain; where it remains 5 to 15 minutes. 

 Then 



JJish II, containing 5 per cent, acetic acid (I to 20); where it 

 remains to 1 miu. The acid removes the excess of stain. 



Dish TIT, water to rinse off the acid. The section can now be 

 placed under the microscope covered with cover-glass to see if 

 the intensity of the stain is sufficient or too great. A second 



