INTBODUCTION. 3 



minerals, rocks, and chemical substances, elemen- 

 tary and otherwise, are found in Nature in such 

 minute particles as to render them suitable for 

 immediate examination and study under the 

 microscope, but, in the majority of instances, it 

 is necessary either to pulverise, grind them down 

 into the thinnest possible sections or sheets, or 

 to precipitate them by chemical means ere they can 

 be brought within the range of observation, and 

 thus the petrologist must be provided with chisels, 

 hammers, files and stones for grinding and polish- 

 ing, and a variety of instruments adapted to the 

 collection and subsequent treatment of specimens, 

 whilst the chemist will require blow-pipes, test 

 tubes, re-agents and balances, &c., &c. For 

 investigations in the organic world, the vegetable 

 histologist must provide himself with a vasculum, 

 a trowel, dipping bottles, and all necessary col- 

 lecting apparatus of all kinds, and' with all the 

 various instruments necessary to facilitate the 

 examination of the unicellular and more delicate 

 forms of plant life, whilst the more highly organised 

 and complex examples will require dissection or 

 sectionising and, in many cases, chemical treatment 

 before they can be examined to any useful purpose. 

 The animal histologist again will find his work 

 inextricably connected with that of his brother 

 botanist, and, to a large extent, will work hand in 

 hand with him, but, as his observations and 

 inquiries progress, there will arise necessities for 

 a collection of tools including scalpels, scissors, bone 

 forceps and saws, needles, forceps of different sizes 

 and forms, section knives, as well as the all-impor- 

 tant and indispensable microtome ; whilst both 



