14 PRACTICAL PHOTOMICROGRAPHY. 



and Otto N. Witt, the former of Spain, the latter of Prussia, 

 have succeeded in producing a magnificent set of photographs 

 of the Diatomacese of Hayti, West Indies. These collabora- 

 tenrs found that they obtained the best results, or rather the 

 only good results, by using the wet collodion process. The 

 writer, while inclined to traverse this assertion of the superior- 

 ity of wet collodion over suitable gelatine emulsion, will have 

 occasion to ad vert to the modus operandi of these undoubtedly 

 skillful and successful workers in a later part of this book. 

 Dr. R. Zeiss, of Jena, has lately exhibited certain photographs 

 of A. Pellucida and P. Angulatum, which in Britain excited 

 considerable comment of a highly favorable kind. The late 

 Isaac H. Jennings produced some very creditable photographs 

 of diatoms, notably one of N. Lyra; and his treatise on Photo- 

 micrography is one of the best in the English language, 

 though late optical and photographic advances have made the 

 book a little out of date.* Another work worthy of perusal, 

 on account of the careful treatment in brief space of the opti- 

 cal part of the subject, is that by Dr. E. C. Bousfield, who is 

 not only an adept with the microscope but has been highly 

 successful in the department of photo-micrography.f 



Still confining himself to work that he has seen, the writer 

 would now draw attention to the magnificent " critical image- 

 photographs " of Mr. E. M. Nelson, of London. A microscop- 

 ist of long and varied practice, of consummate skill, and pos- 

 sessed of an intimate knowledge of microscopic optics, Mr. 

 Nelson has laid himself out for the most difficult branches of 

 photo-micrography, the photography of the highest possible 

 resolutions of such subjects as muscle-fibrils, " secondary struc- 

 ture " of the diatomacese, and ordinary diatom structure of the 

 most delicate kind. To Mr. Nelson the writer owes practi- 

 cally all the knowledge he has of microscope-manipulation, 

 and to Mr. Nelson's unstinted instruction and careful explana- 

 tions the writer is indebted for any measure of success he has 



* Photo-micrography ; or, How to Photograph Microscopic Objects. 

 By I. H. Jennings. London : Piper & Carter. 1886. 



f Guide to the Science of Photo-micrography. By Edward C. Bousfield, 

 L. R. C. P. London : W. Kent & Co. 1887. 



