PRACTICAL MICROSCOPY. 



he will see his way to carry on experiments in a rational 

 manner, as often as fresh problems are presented to him. 



Again, no inexpensive work upon practical microscopy 

 brings the subject down to the present time ; this and 

 other minor details urged us to cut out a path for our- 

 selves, and produce a treatise which might be of use to the 

 student. 



In using the microscope as a means of gaining an insight 

 into the anatomy or life-history of forms only faintly dis- 

 tinguished by the unassisted eye, the student must be 

 prepared to exercise a certain amount of patience ; skill in 

 manipulation comes by practice only, and before com- 

 mencing with any investigation, all preconceived notions 

 should be cast aside, the observer being guided chiefly by 

 the results of his own observations. 



Isolated observations should never be considered con- 

 clusive ; experiments require frequent repetition under very 

 varying conditions before we can accept the results as true 

 interpretations of what we have actually seen. We should 

 also be careful to take into account the degree of per- 

 fection of our instruments as well as our own capability 

 of vision ; what one observer will see, another will fail 

 to detect, and if any preconceived notions exist, the 

 observations are sure to be moulded after the same 

 fashion. 



Expertness in microscopy is only to be attained by study 

 and practice, and as it is necessary, in order to progress, 

 that we take up the subject where our predecessors left off, 

 it is necessary to become acquainted with what has been 

 done previously, and this may be arrived at by the perusal 

 of old standard works upon the science, such as those of 

 Baker, Pritchard, and Goring, or the more recent work of 

 Mr. Quekett's, ' The Practical Treatise on the Use of the 

 Microscope.' These works, though old, are valuable, and 



