112 On a New Suh-gtage for the Microscope, 



acid, as directed by Moseley, larger clear spaces were procured where 

 this network would be more distinctly seen, and from one of which 

 the above figure was drawn. In the preparations made without the 

 use of gold, the fine nerves were most easily seen by suddenly lift- 

 ing the focus a trifle by the fine focussing screw, when these fine 

 threads became apparent by the peculiar refracting power of their 

 material ; then by carefully adjusting the illumination they could be 

 refocussed for more easily. A few days since I tried to photograph 

 this network, but did not succeed then to my own satisfaction, other- 

 wise I had intended to forward a figure from the negative instead 

 of the above drawing. 



Some one had recommended the use of a solution of hydrate 

 of chloral in the examination of some kinds of living specimens 

 when under the microscope ; adopting the hint, I may here state, 

 that I found it to answer remarkably well in quieting the move- 

 ments of the tadpole, in the strength of 5 grains to 1 ounce of 

 distilled water. For insect larvae and infusoria its application 

 generally quickly renders them quiet, and no doubt to those 

 studying the rotifers in which the motions are so exceedingly rapid 

 this solution, of possibly a different strength, would prove most 

 useful. I may here also note that it was adopted successfully in the 

 strength of 10 grains to 1 ounce of water on a large slug, for it is 

 diflScult to kill these creatures by ordinary means so that the tissues 

 shall remain in an extended state ; indeed the mollusca generally 

 become very contracted when immersed in any stimulating fluid for 

 the purpose of killing them quickly ; so possibly this article may be 

 a more or less merciful means of treating these and other creatures, 

 without interfering with the normal appearance of the tissues. 



IV. — On a New Sub-stage for the Microscojpe, and on certain 

 Appliances for Illumination. By Edwin Smith, M.A. 



The microscope to which I have recently added the very convenient 

 improvements in question is a Crouch's Students' Binocular, with 

 circular revolving stage. In the first place, I have found much 

 advantage from a second diaphragm behind the one usually accom- 

 panying the Webster's condenser. Some such condenser is indis- 

 pensable, if an equally illuminated field is to be given to both eyes, 

 with a §-inch or |-iuch objective. The ttvo diaphragms work together 

 to afford a great range of effects, both for spot-lens and for oixlinary 

 thorough light. Two large openings being brought opposite to 

 each other, give perfect command of the secondary stage below with- 



