STRUCTURE OF LIVING THINGS 177 



parent were at first cut from the fresh tissues, and 

 examined by transmitted light. This did very well in 

 a rough way, but better results were obtained by hard- 

 ening the tissues in alcohol or chromic acid, when 

 wonderfully fine sections could be cut and rendered 

 translucent by soaking in varnish, in which they were 

 preserved for study with the microscope, between two 

 plates of glass. The sections were stained with various 

 dyes, such as carmine, log-wood, the aniline dyes, etc., 

 and it was found that the nuclei of the cells and the 

 granules and fibres both in the minute cells and in the 

 surrounding substance manufactured by them, could be 

 distinguished more clearly by means of their differing 

 affinity for the dyes. And whilst endless section-cutting 

 and staining and careful drawing and record of the 

 structure discovered, was proceeding in hundreds of 

 laboratories other observers especially devoted them- 

 selves to the difficult task of seeing the cell-substance or 

 protoplasm and its nucleus under the highest power of 

 the microscope, whilst still alive ! It would seem a 

 hopeless task to examine with a high-power microscope 

 the cells (less than a thousandth of an inch broad) inside 

 the solid stem or leaves of a plant or of an animal's body 

 without killing the plant or animal and the cells of which 

 they consist. As most of my readers know, the front 

 lens (or " glass ") of a high-power microscope has to be 

 brought very close indeed to any object in order to 

 bring it into focus as near as the one twenty-fifth of 

 an inch. Then the object examined must be very small 

 and transparent, in order that the light may pass through 

 it, as through the slide-picture in a magic lantern, and 

 so form a clear, well-defined picture in the focus of the 

 microscope, where the eye receives it. 



Fortunately, there are some facts about living cells 

 or corpuscles of protoplasm which enable us to examine 



