DECOMPOSING BLOOD, ETC. 



233 



refractive index, and (as required to obtain the greatest advantage 

 the use of the objective offers) upon a flint glass slide and cover. 

 ( Vide a letter from Dr. van Heurck, with figures from his photo- 

 micrographs, which unfortunately do not do justice to his work, 

 in the English Mechanic^ Oct. 7, 1892.) 



The preparation from which my photograph. Fig. 63, is made 

 is of a wet one : — A saturated solution of potassic acetate and 

 distilled water, equal parts ; while the photo-micrograph was made 

 with an old Gundlach immersion, i/i5th, and which was employed 

 for all the photographs except No. 7 (Fig. 62) 



Fig. 63. — A spirillum and free joint, showing flagella and changes, with 

 spores that have occurred in the plasm, x 520. 



Upon close examination, I at last found a field of view in 

 which both the mature spirillum, with its flagellum at each end, 

 and a separate joint lying near, each showing the differentiation 

 that has been alluded to in such a position that both could be 

 photographed at the same time. For many years, or at least 

 since making my experiments on the organisms found in the 

 excrement of the domestic goat and goose,* 1 have been exceed- 



* Vide Journal R, M, 5. , Dec. , 1 882. 



