Pliotograpliing Histological PrejMrations hj Sunlight. 179 



No. 3. A section of the eyelid of a calf, showing sebaceous glands 

 surrounding a hair. Magnified 500 diameters by Powell and Lea- 

 land's immersion |th. Negative No. 367, New Series. From pre- 

 paration No. 3640, Microscopical Section. The preparation was 

 made by Dr. E. M. Schaefier. The section was stained with car- 

 mine, and mounted in Canada balsam. The lobules of the sebaceous 

 glands have been focussed upon for the display of the glandular 

 epithelium ; the hair and adjacent j)ortion of the hair folHcle appear 

 of course somewhat out of focus. 



No. 4. Section of the kidney of a frog. Magnified 400 diameters 

 by PoweU and Lealand's immersion |th. Negative No. 373, New 

 Series. From preparation No. 3018, Microscopical Section. The 

 preparation was made by Dr. J. C. W. Kennon. The section was 

 stained in carmine, and mounted in Canada balsam. The photo- 

 graph shows some of the tuhuU uriniferi cut transversely ; others 

 more or less obliquely. 



No. 5. Section of the liver of a pseudo-triton. Magnified 500 

 diameters by Powell and Lealand's immersion |th. Negative 

 No. 371, New Series. From preparation No. 3573, Microscopical 

 Section. The preparation was made by Dr. J. C. W. Kennon. The 

 section was stained in carmine, and mounted in Canada balsam. 

 The photograph shows the polygonal cells and their nuclei. The 

 double contours between some of the cells indicate the position of 

 the ultimate gall ducts. 



No. 6. Section of the ovary of a cat. Magnified 400 diameters 

 by Powell and Lealand's immersion ith. Negative No. 292, New 

 Series. From preparation No. 3031, Microscopical Section. The 

 preparation was made by Dr. J. C. W. Kennon. The section was 

 stained with carmine, and mounted in Canada balsam. The photo- 

 graph shows the connective tissue of tha ovary, with a number of 

 immature ovules imbedded. The nuclei of the connective tissue are 

 well defined, and in several of the ovules the germinal vesicle is 

 distinctly seen. 



No. 7. Another portion of the section shown in No. 6. Same 

 power. Negative No. 293, New Series. The photograph shows in 

 the centre an ovule, with germinal vesicle and germinal spot well 

 defined. The ovule is surrounded by several layers of cells, the 

 nuclei of which are best seen on the right side. These belong to 

 the immature zona granulosa. Externally is the connective tissue 

 of the ovary. 



No. 8. Another portion of the same section. Same power. 

 Negative No. 294, New Series. This photograph represents a 

 nearly ripe Graafian follicle, lined by a layer of cells (the zona 

 granulosa) four to six deep — the nuclei of this layer are well defined. 

 On one side an ovule is imbedded, in which the germinal vesicle and 

 germinal spot are distinctly shown. The portion of the zona 



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