THE DRAWING OF MICKOSCOP1C OBJECTS. 



297 



sion which the observer has appropiated to himself, whether it be 

 correct or incorrect. Absolute truth to nature must always remain 

 for the microscopist an ideal, which he indeed strives to approach 

 but can only approximately attain. His drawings are true to 

 nature, in the most favourable case, in those points alone for the 

 delineation of which they were intended. The author himself, if 

 he refers to them again after the lapse of some years, will not 

 expect to find more in them. 



As the accurate reproduction of the outlines in complicated 

 drawings is a difficult matter even for the practised hand, numerous 

 aids have been invented by means of which it is possible to project 

 the microscopic image upon the plane of the paper. The better 



FIG. 166. 



known of these appliances may be brought under the following 

 categories : 



(1.) Devices which so reflect the pencils of light issuing from 

 the eye-piece that the image is projected upon a vertical or more 

 or less inclined surface. The last reflecting surface is hence pro- 

 vided with a small aperture, or is of very small extent, so that in 

 either case the eye sees through a portion of the pupil the point 

 of the pencil with which the outlines of the image are being traced. 

 The pencil is therefore seen directly, whilst the microscopic 

 image is seen by reflexion. But since a single reflexion involves, 

 as we have already stated, a half-inversion of the image, those 



