178 0)1 an Improved Method of 



attainable by sunlight, used as above described, that I should rarely 

 take the trouble to set up the battery and work the electric lamp, 

 unless it was desirable to work at night or in unfavourable weather. 

 It only remains to append some examples of the results attained 

 by sunlight employed in this manner. In selecting a few negatives 

 for this purpose I have preferred to confine myself to those which 

 represent normal tissues, magnified to the moderate extent of four 

 or five hundred diameters. I have done so because I believe that 

 the greatest practical results are to be anticipated from the repro- 

 duction of similar objects with like powers. I would refer those 

 who are curious as to the possibilities with higher powers, to the 

 photographs accompanying my " Memoranda " on the Test Podura, 

 and on Pleurosigma angulatum and P. formosum, the majority of 

 which were produced by the methods above laid down. Among 

 the views will be found one of P. angulcdum and one of P. forvno- 

 sum, each magnified 4500 diameters. The following is a brief 

 description of the subjects represented in the photographs which 

 accompany the present paper. 



[The following photographs have been received by us, but of course are not 

 reproduced, being representations of objects familiar to most anatomists. They 

 are, some of them, very correctly done ; but we fear they do not yet represent 

 all that is seen with the eye. Some of them, as for example Nos. 3, 4, 5, are, 

 we fancy, rather imperfect representations of the objects they are intended to 

 represent. — Ed. * M. M. J.'] 



No. 1. Photograph representing a bundle of the striated mus- 

 cular fibres of the mouse. Magnified 500 diameters by Powell and 

 Lealand's immersion -|th. Negative No. 368, New Series. From 

 preparation No. 2338, Microscopical Section. The preparation was 

 made by Dr. J. C. W. Kennon. The capillaries were injected with 

 carmine, and the fragment selected is mounted in Canada balsam. 

 For photographic purposes the focal ^.djustment was arranged to 

 display the transverse striae, and hence the capillaries appear some- 

 what out of focus. 



No. 2. Portion of the peripheral wall of one of the alveoli of the 

 lung of a frog. Magnified 500 diameters by Powell and Lealand's 

 immersion -|th. Negative No. 365, New Series. From preparation 

 No. 3639, Microscopical Section. The preparation was made by 

 Dr. E. M. Schaefier, one of the assistants in the Microscopical Sec- 

 tion. The vessels were injected with a dilute silver solution, and 

 the preparation, after staining with carmine, was mounted in Canada 

 balsam. The photograph represents a small artery breaking up 

 into a network of capillaries. The cells of the endothelium are 

 mapped out by the silver, and the carmine-stained nuclei appear in 

 many places. This picture is introduced for comparison with the 

 best of those obtained with artificial light appended to my report on 

 the Histology of Minute Blood-vessels. 



