INTRODUCTION. xxiii 



fluid, such as methylated spirit, ' Wickersheimer's fluid, 1 or 

 boro-glycerine. 



I should strongly advise students to adopt the plan so 

 much insisted upon by Professors Huxley and Martin in 

 their Elementary Biology, of making sketches of their 

 dissections. Even a rough drawing, if the various parts 

 are properly named, and especially if they are further 

 distinguished by different colours, forms a far better 

 memorandum of work done than any mere description. 



1 This fluid is made as follows : dissolve 100 grams of alum, 25 of 

 common salt, 12 of saltpetre, 60 of potassic carbonate, and 20 of 

 arsenious acid in 3 litres of boiling water, and add I '2 litre of glycerine 

 and 0*3 litre of methylated alcohol. 



