76 THE MICROSCOPE. 



folded upon itself. The peculiar folds would lead to the supposi- 

 tion of the existence of a limiting membrane; for, if it were simply 

 a plastic homogeneous mass, it would be natural to suppose that it 

 would coalesce and all wrinkles disappear. Fig. 8 shows a white 

 corpuscle, or "leucocyte," from the blood of. the newt. I wish to 

 call attention to the peculiar manner in which some of its nuclei 

 seem to be connected. Fig. lo shows a red corpuscle of the newt's 

 blood. It was stained by a slightly different process. In this cor- 

 puscle a very peculiar condition is seen. In spreading upon the 

 slide, something was evidently ruptured, and allowed the nucleus to 

 escape ! It also looks as though some of the substance of the cor- 

 puscle had run out, and between the nucleus (the blue part) and the 

 corpuscle will be seen a peculiar transparent something which is only 

 distinguished by its apparent wrinkles or foldings. Is it possible 

 that this can be the oft-claimed but non-supported membrane ? 



A MOUNT FOR LOW POWERS. 



A BEAUTIFUL slide for low powers may be made of a part 

 section of a human heel, cut from bottom upward. Let the 

 section be about three-eights of an inch deep and not less than one 

 two-hundredth of an inch thick. Place the section in picro-car- 

 mine for seven minutes, which will give the skin, muscle and adipose 

 tissue each a different shade. W'ash off excess of color, place for 

 a few moments in oil of cloves to clear. 



Have a bottle of Dean's gelatine, medium warm, in water bath. 

 The slide, cover and section may also be dropped into the warm 

 water. Place the wet section on the warm slide, appl}- the gelatine, 

 and cover. 



The spiral sweat-ducts in the skin will now show conspicu- 

 ously. 



Mounting in balsam makes the section too transparent to show 

 these ducts well. 



A thin section should be mounted in balsam to show the sweat 

 glands and straight portion of the ducts through the muscle, as 

 these do not show well in the thick section, and treatment which 

 serves best to bring out the spiral portion of the ducts. 



In ordinary mounting with both benzole balsam and chloroform 

 balsam, I found it difficult to get the balsam to fill out to all parts 

 of cover. Heat will not serve to spread it, as in pure balsam, but 

 a drop of either benzole or chloroform applied to edge of cover 

 will at once bring out the balsam to edge of cover. 



R. N. Revnolds. 



