PEAOTICAL PHOTO-MICROGRAPHY. 13 



give valuable instruction to beginners as he most generously 

 did to the writer. No man has worked more perseveringly or 

 more successfully in this branch of science than Dr. Maddox, 

 and no man ever got less reward beyond that of conscious 

 merit than our good friend. His photographs of Pleuro- 

 sigma angulatum X 3,000, of many micro-organisms, and of 

 various other subjects still rank among the best works that 

 have been produced. 



The work of Dr. Woodward of the U. S. Army was so re- 

 markable and so excellent as to mark, or even to make, an era 

 of itself. This scientist was a microscopist of the very fore- 

 most rank, a generous government placed at his disposal 

 the very best instruments, and the results amply justified the 

 country's confidence, for Dr. Woodward's photo-micrographs 

 of Amphipleura pellucida, of Nobert's test plates, of the 

 well-known test " Podura scales," as well as of many physio- 

 logical and pathological subjects have seldom if ever been 

 equalled. If these works of Dr. Woodward's are ever beaten 

 the superiority will be due to late improvements in optical ap- 

 pliances, and to the use of more sensitive " color-correct " plates 

 for photography. 



Dr. Koch, the eminent authority on micro-organisms, has 

 produced fine photographs of bacteria, and Dr. E. M. Crook- 

 shank, Professor of Bacteriology at King's College, London, 

 has published not only a number of photographs of Bacteria 

 but also, in a succinct and ably written book, his methods of 

 producing his photographs with capital diagrams of his ap- 

 paratus.* 



The Diatomacese, as might be expected from their beauty, 

 have always been favorites with the photo-micrographer, but 

 from their formation they have always proved severe tests for 

 the powers of those who have attempted them. Besides the 

 micrographs of Dr. Woodward we must notice some very fine 

 work by Dr. Mercer, also an American citizen. Drs. Aber- 

 crombie and Wilson in England were very successful in photo- 

 graphing the diatomaceae, and lately Messrs. A. Truan y Luard 



* Photography of Bacteria, by Edgar M. Crookshank, M. B., F. R. M. S. 

 London: H.K.Lewis. 1887. 



