318 NATURAL HISTORY OF OUR SHORES 



(" brown cement ") ; a 1-oz. bottle of asphaltum ; a 1-oz. 

 bottle of matt black ; a few old cambric handkerchiefs ; 

 slide labels ; 1 box " clips" 



This is a fair, although by no means " complete," outfit, 

 but it will allow of really good work, as I have said. The 

 microscope maker or dealer will supply the whole, and 

 with the exception of the microscope and microtome the cost 

 will not be more than about forty shillings. 



Now dissolve some celloidin chips in a mixture of equal 

 parts ether and absolute alcohol, to about the consistency 

 of ordinary syrup ; keep this in a well-stoppered bottle, in 

 a cool place. 



Take a narrow- necked, glass-stoppered bottle, of six-ounce 

 capacity. (This should be one of dark blue or black glass, 

 otherwise stick some black paper around it.) In this 

 bottle put 100 c.c., or say four and a half fluid ounces, of 

 distilled water. Then remove the label from the tube of 

 osmic acid, and clean off all the gum smear ; put the tube 

 and its contents into this, and crack it with a glass rod, 

 leaving the glass fragments in (do not let wood or any 

 organic matter come in contact with this solution) ; keep 

 from breathing the osmic fumes, as they are very irritating 

 to the nose and throat. Label the bottle " Osmic Acid, one 

 per cent.," and keep it in a dark place, as light decomposes 

 this solution. 



Now for the practical part. 



It is customary to commence instruction in microscopic 

 mounting by the most simple processes viz. dry mounts, 

 etc. We shall reverse this method, and begin with what 

 is usually considered the most difficult, then the remainder 

 will follow easily. 



u 



Objects that are required to demonstrate minute 

 structure that is, their " histology " whether to be 

 sectioned or mounted entire, require to be treated with some 

 reagent that will harden the cell contents without in any 



