CHAPTER XII. 



PHOTOGRAPHY OF BACTElilA. 



The production of pictures of microscopic objects by photographic 

 means was attempted at an early date. Some authorities regard 

 the very earhest recorded experiments as being the first experi- 

 ments aHke in photography and micro-photography. , The experi- 

 ments of Wedgwood and Sir Humphry Davy were embodied in 

 a paper read before the Exjyal Institution in 1802. They obtained 

 with the solar microscope impressions upon paper, and with greater 

 success upon white leather, though the results were transitory when 

 exposed to daylight. 



In 1816 Nicephore Niepce described his experiments in con- 

 nection with fixing the image obtained by the camera. He was 

 at first only able to obtain negatives, and these' were transitory. 

 But, after joining with Daguerre, who had been experimenting 

 in the same direction, a process was invented which was published 

 in 1839 under the name of daguerreotype. 



This invention, and the rapid improvements which followed, 

 were taken advantage of by Reade, Donne, Hodgson, Kingsley, and 

 Talbot, who were .early workers in the field of micro-photography. 



So early as 1845 it is stated that Donne produced a work 

 illustrated with engravings copied from daguerreotypes. 



Subsequently this interesting branch of photography was taken 

 up by many in France and Germany, in America, and in England. 

 Of those to whom we are indebted for the literature of the subject, 

 and for many improvements, the names of Wenham, Dancer, 

 Draper, Maddox, Shadbolt, Redmayne, Woodward, Highley, Deecke, 

 Moitessier, Gerlach, Koch, Sternberg, Frankel, Pfeiffer, and Pringle 

 may especially be mentioned. 



Of these workers the name of Woodward stands pre-eminently 

 foremost. His skill in microscopical manipulations, combined 

 with access to the very best apparatus and objectives, placed at 



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