98 



THE AMERICAN MONTHLY 



[May, I 



care, even though it be unattractive 

 in appearance, and such a slide 

 "would be acceptable to most per- 

 sons ; but the trouble exchangers 

 meet with is, that they receive 

 slides that show no indications of 

 care in their pre]3aration, full of 

 dirt and bubbles, and only tit to 

 throw away. 



We cannot do more than to ask 

 our subscribers not to offer any- 

 thing that is not really good, in the 

 exchange column. 



Sometimes correspondents offer 

 material without asking for any- 

 thing in return. Many persons are 

 so inconsiderate that they do not 

 think of the labor involved in re- 

 plying to inquiries for material so 

 f;enerously offered, and they, there- 

 ore, send their requests on postal 

 cards. The least they can do, it 

 seems to us, is to send a stamped 

 and addressed envelope to the per- 

 son who offers the material. One 

 gentleman writes us that he has 

 sent out no less than fifty specimens 

 to applicants " as well as furnishing 

 the three-cent stamp when request 

 was made by postal card," etc. 



CORRESPONDENCE. 



To THE Editor : — Dr. Hamlin's new 

 wfax-cell, described in the March number, 

 is an invention which entitles him to the 

 gratitude of all workers with the micro- 

 scope. My experience, however, moves 

 me to offer two suggestions in regard to 

 the method of its manufacture ; 1. Be- 

 fore applying pressure to the outer edge 

 of the disc, a little turpentine should be 

 applied to the lower surface with a brush, 

 extending to the proposed width of the 

 ring ; 2. Instead of a slight moistening of 

 the knife-blade, water should be used 

 freely. 



Respectfully, 



J. G. 



Ridgewood, N. J. 



NOTES. 



— Mr. M. A. Veeder contributes the 

 following ingenious suggestion, in a late 

 number of The American Naturalist. 



"In order to reduce the quantity of 

 water containing infusoria, obtained by 

 means of a collecting bottle or otherwise, 

 an easy and effective method is to allow 

 the liquid to stand in a bowl until it has 

 settled, and then take up the water by 

 means of a sponge placed in a pouch 

 made of fine silk. If the water be allowed 

 to soak into the sponge very gradually, 

 and a slight pressure be given before re- 

 moving it from the bowl, so as to wash 

 away any adherent particles, even the 

 liner forms of animalculas diffused through 

 a pint of water may be left in great abun- 

 dance in a quantity of water not larger 

 than a tablespoonful." 



— The American Society of Microsco- 

 pists meets this year at Detroit, and a 

 large attendance is expected. The meet- 

 ing begins on the 17th of August and 

 continues to the 20th. When the final 

 arrangements for the meeting are an- 

 nounced we will have more to say aboyt 

 the prospects of the Society, which has 

 our best wishes. 



— The first two numbers of the seventh 

 volume of the Bulletin of the Torrey 

 Botanical Club have reached us, and we 

 are pleased to notice that there is a nota- 

 ble improvement in its appearance, which 

 indicates a renewal of activity in the Club, 

 and an intention to make the Bulletin a 

 better paper than it has been of late. Mr. 

 W. H. Leggett is the editor, but he is 

 now assisted by Mr. W. R. Gerard, who 

 is well known as a student of the Fungi. 



The subscription price is $i.oo per 

 year. All botanists should take the Bul- 

 letin. 



— We have received from Mr. Geo. O. 

 Mitchell, of Hanover, N. H., an excellent 

 nickel-plated compressorium, such as he 

 manufactures for sale. This instrument 

 is a modification of the well-known com- 

 pressorium devised by Mr. Wenham. It 

 is much cheaper than the latter, costing 

 only $1.50 of lacquered brass, and $1.75 

 nickel-plated. 



A compressorium is a very useful ac- 

 cessory, and it is of great service in the 

 study of minute Crustaceas and Infu- 

 soria. 



