CHAP, viii.] HELIOGRAPHY PHOTOLITHOGRAPHY. 325 



Natural history, medicine, anatomy, and physiology are no less 

 indebted to photography, through the infinite resources which it 

 provides for their special study. 



Preparations which can only be preserved at a great expense, the 

 true forms of vegetable, animal, or human anomalies, once fixed by 

 light, with their most minute peculiarities, thus multiplied for science, 

 will in the same way multiply the subjects for study by serving as a 

 sound basis for the discussions of scientific men. Thanks to photo- 

 micography and the enlarging processes, an immense assistance has 



FIG. 225. Photographic microscope. 



been and will still be rendered in the study of the animal and vege- 

 table tissues, and of the infinitesimally small creatures revealed by 

 the microscope. What we have said for man and the human races 

 may be repeated for the endless varieties of animal and vegetable 

 life, which the most talented draughtsmen can doubtless delineate, 

 but not without a great expenditure of time and toil. Besides, these 

 very talented draughtsmen are rare. It is not every explorer, every 

 traveller in untrodden or unknown lands, who can pretend to possess 

 this difficult art. Furnished with a photographic apparatus and the 



