The Microscope. 249 



We are confident that the experiment to be tried at the next meeting 

 will prove a success, but in order to make it so, Dr. Reeves and 

 other experts in practical microscopy should be on hand. 



Acknowledgments. — From Dr. James E. Reeves, Chattanooga, 

 Tenn., three slides in the perfection of Dr. Reeves' well-known 

 style ; from Dr. H. H. Ganz, Clifton Springs, N. Y., sample of his 

 " Eureka Bottle Covers." It strikes us that microscopists will find 

 these covers veiy useful for covering reagent and stain bottles. 

 They are simple and cheap, and commend themselves ; from E. H. 

 Griffith, cleaned diatoms from New Hampshire. 



TECHNOLOGY. 



Picko-Carmine. — The Magazine of Pharmacy gives the follow- 

 ing method for the preparation of picro-carmine: Dissolve half a 

 gramme of carmine in 100 cc. of water, to which has been added 5 

 cc. of a one per cent, solution of soda. Boil, filter and add sufficient 

 distilled water to make 100 cc. of the stain. Mix with an equal 

 volume of water, and add a one per cent, solution of picric acid. 

 The turbidity thus produced soon disappears ; if not, the fluid has 

 been over-neutralized. 



ABSTRACTS. 



THE EGGS OF THE GNAT. 



TN some notes on the development of the gnat, contribiited by Mr. 

 -*- Harry Thomas to Science Gossip, the writer says : " The 

 female gnat lays her eggs, arranged spirally, in a sausage-shaped, 

 colorless jelly, varying from one- quarter inch to one inch in length, 

 beneath the surface of still waters. I obtained specimens during 

 the months of August, September and the early part of October. 

 They were found usually attached to the side of the vessel, by an 

 adherent disk terminating a prolongation of their upper extremity 

 just beneath the water ; but sometimes unattached, suspended 

 several inches beneath the water, when the disk reaches to and floats 

 upon the surface. When first deposited, the eggs are closely packed 

 together, forming a short, brown string. In a very short time the 

 connecting envelope absorbs the surrounding water till it has 



