THE PREPARATION OF ANIMAL TISSUES. 57 



Lungs of a kitten, or puppy. Distend these with 

 a \ per cent, solution immediately after death, then 

 ligature the trachea, and sink them in alcohol till 

 required. 



Tendon. Tendons and their sbeaths are covered 

 by endothelium. Pinch the tail end off a recently 

 killed mouse, and wash the fine tendon fibres thus 

 drawn out in distilled water, and treat with a ^ per 

 cent, solution. Take another set of these fibres, 

 pencil off their endothelium with a camel-hair brush 

 dipped in distilled water, then silver. This shows 

 the cell spaces in tendon. 



Cornea. The cell spaces of cornea may be shown 

 by scraping away the epithelium from the anterior 

 surface of the cornea of a pithed frog, then applying 

 a 1 per cent, solution till greyish white. The 

 cornea must be snipped at its edges, after being 

 silvered, to make it lie flat on the slip. A rat's 

 cornea may be likewise treated and stained with 

 logwood. 



Blood Vessels. Kill a small quadruped by bleed- 

 ing. Syringe out the blood vessels with distilled 

 water; then inject a % per cent, solution. Use the 

 spleen, mesentery, and intestines. The spleen must 

 be hardened in alcohol, and sections cut, exposed 

 to light, after staining with logwood, or not, as 

 desired. This shows the endothelium of the venous 

 sinuses. The intestines must be cleared of their 

 contents by distilled water ; exposed to light in a 

 saucer containing water ; a piece of small or large 

 intestine is snipped out, laid on a slide with its 

 mucous membrane upwards, which is gently scraped 

 away, the muscular and serous coats remain, and 

 are to be mounted in balsam. 



