14 HISTOLOGY 



1. Frog's Blood. Take a drop of the blood on a coverslip diluting with a drop of normal salt solution 

 (75 %) Place on a slide and examine under the high power of the microscope. Draw the red corpuscles 

 shewn in full face and in side view. Move the slide about to find white corpuscles (leucocytes). 



Place a drop of acetic acid (i %) at one side of the coverslip and allow it to diffuse under. Observe the 

 nuclei. 



Make a film by thinly smearing one side of a coverslip with blood, and dropping it into absolute alcohol. 

 Place for 3 4 minutes in methylene blue and examine under the high power. Observe the red blood corpuscles 

 with nuclei clearly stained. Also the leucocytes, some hyaline and others with deeply stained granules. 



2. Mammalian Blood. Draw a drop of blood from the finger with a clean needle and dilute with normal 

 salt solution as before. Observe the red corpuscles, shewn in full face, in side view, and in rouleaux. Search 

 for white corpuscles. Irrigate as before with acetic acid (i %) and observe that the latter alone are nucleated. 









3. White Fibrous Tissue. Pull up with fine forceps the thin connective tissue between the muscles of 

 the frog's thigh and cut off a small piece with scissors. Spread out on a dry slide with needles, and carefully 

 place over it a dry coverslip, allowing a drop of normal salt solution to diffuse under. Examine under the high 

 power of the microscope. Observe the wavy bundles of fibrillce crossing each other in every direction, and 

 the connective tissue cells, which will be made clearer by irrigating with acetic acid (i %), while the fibrillae will 

 disappear. 



