APPLICATIONS OF PHOTOMICROGRAPHY 239 



teaching and lecturing need hardly be emphasised, and 

 it is in this connection that the process of lantern-slide 

 making is described. 



The topics selected for discussion are confined to those 

 illustrated by the plates ; though restricted in this way 

 they are sufficient to give some idea of the wide range of 

 photomicrography, its value in various professions and 

 sciences, and great superiority, in most particulars, over 

 any method of drawing. The modifications of general 

 processes, and the special methods described refer par- 

 ticularly to the plates, but may be applied with very little 

 variation to many other subjects. In order to make the 

 descriptions of the plates as complete as possible an 

 outline is given of the methods employed to prepare 

 some of the objects. They are in the main the ordinary 

 processes familiar to microscopists, but may be found 

 useful by some readers, as success in photomicrography 

 depends in no small degree on suitable preparation of the 

 specimens. Further details and devices applicable to 

 special cases must be sought for in one or other of the 

 many excellent text books dealing with micro -technique. 



The use of Photomicrography in Pathology and 

 Medical Practice (Plates 31 and 32). There are many 

 directions in which photomicrography is of service in 

 medical study and practice, and, as the subjects which 

 present themselves range from the most minute bacteria 

 to entire growths and organs of considerable size, an 

 acquaintance with the methods of high-, medium-, and 

 low-power photomicrography is desirable. To be pre- 

 pared for any contingencies a set of objectives such as 

 that mentioned at the foot of page 81 (No. 1) should be 

 obtained. No. 3 on page 82 is the set usually in the hands 

 of medical men, but the omission of a lower power than 

 f " is rather a drawback. 



A series of photomicrographs attachable to the notes 

 forms an excellent record of progress in certain inoperable 



