98 



THE AMERICAN MONTHLY 



[May, 



care, even tliougli 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 preparation, 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 generously 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 

 wax-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 T/ie 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 

 finer forms of animalculee 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 about 

 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 Crustaceae and Infu- 

 soria. 



