202 THE AMERICAN MONTHLY [June 



fitting or else supported on a modified form of sub-stage. 



The ingenuity which has been expended on this type of 

 stand is remarkable; most, though not all, of our Eng- 

 lish firms having competed with one another to produce 

 the most attractive instrument at a given price. But if 

 the type itself is not everything that can be wished, it 

 would be unfair to blame the opticians, for they have 

 simply catered for a public want. The demand comes 

 mainly from the teachers in the laboratories of our medi- 

 cal schools, who seem almost with one accord to have cap- 

 itulated to the Continental fashion, and to have advised 

 their students accordingly. 



Now it must at once be admitted that the better forms 

 of small stand are very handy to use, and that they al- 

 low of the manipulation and examination of specimens in 

 fluid 'whilst lying horizontally on the stage. 



There is no doubt that they serve their purpose well, 

 and it would be hopeless, if indeed it were desirable, to 

 attempt to displace them by instruments of larger build. 

 It should always, however, be insisted upon that instru- 

 ments of this type must be constructed as simply and as 

 rigidly as possible. They should be fitted with a large, 

 firm stage, preferably of glass or of some other'material 

 that will resist the action of corrosive and other fluids ; 

 and sufficient space should be given between the pillar 

 and the central opening of the stage to allow of the use 

 of large culture plates, and of ordinary apparatus for dis- 

 section. There should always be a substage fitting, per- 

 fectly centered to the optic axis of the microscope tube ; 

 but it is doubtful whether it is worth the expense to 

 mount the illuminating apparatus for instruments of this 

 kind on a centering and focussing substage. Such in- 

 struments as these should be provided in all cases with a 

 double nosepiece. This type of microscope is common in 

 * the English market at the present time, and appears to 

 meet^with general approval. Several instruments of like 



