180 Photographing Histological Preparations hy Sunlight. 



granulosa reflected over the ovule is composed of two layers of cells, 

 as shown by the nuclei. On the exterior of the Graafian follicle 

 the connective tissue of the ovary and its nuclei can be seen. In 

 the cavity of the Graafian follicle is a quantity of ill-defined gi'anu- 

 lar matter. 



Ko. 9. An epithehal cell and several salivary corpuscles from 

 fresh human saliva. Magnified 960 diameters by Powell and Lea- 

 land's immersion roth. Negative Ko. 408, New Series. One of 

 the sahvary corpuscles is very satisfactorily displayed. 



In conclusion, I cannot but express the hope that my work in 

 this direction may induce other microscopists, and especially those 

 who are conducting original researches, to resort to photography as 

 a means of bringing their results in a tangible form before their 

 fellow microscopists. It wiU be seen from the statements now made, 

 that, with the exception of the mounting of an ordinary solar mirror, 

 no special apparatus is absolutely needed for this purpose which 

 may not be made by the microscopist himself, or at least produced 

 at a very trifling cost. Nothing more than a knowledge of the 

 j^rinciples of photogi'aphy is required. In every case the services 

 of a good dark-room man should be procured, and if the prepara- 

 tions are carefully selected beforehand and the highest wages paid 

 to the best operator attainable, the average cost of the negatives 

 wiU be far less than that of the cheapest and most indifferent draw- 

 ings. Accuracy of representation in these objects can only be 

 satisfied by photography, and photogi'aphy is not only the most 

 accm-ate, but the cheapest and least troublesome method of repro- 

 ducing microscopic objects. Of course much of the beauty of the 

 result will depend on the character of the preparation selected. 

 But in a general way the preparations best fitted for study are 

 those best fitted for photography. If photographic representation 

 was universally demanded, a higher class of preparations than those 

 which now satisfy too many microscopists would become indis- 

 pensable, and the vague description, based on clumsy or imperfect 

 preparations, which too often disfigures microscopic literature, would 

 be replaced by a more accurate representation of the actual facts.' 



AvMY Medical JIusetjm, Microscopical Section. 



