164 The Micuoscope, 



places, which he names, including specimens found in the south-west 

 of Lake Baikal in Asia. Monographs on the fresh-water sponges 

 have been written by him. and by Dr. Vedjovski, of Prague, 

 Bohemia. 



Fresh water sponges may be found in most of our rivers, ponds 

 and lakes, attached to the undersides of submerged logs, and pieces 

 of wood, or stones. Old rafts of logs that have been lying for some 

 time at the mill-dam, yield fine specimens. They are sometimes 

 attached to weeds, Anacharis canadensis and Valisneria spiralis 

 being their special favorites in some waters. I have found them on 

 the ground where the light has been partly excluded, darkness being 

 generally favorable to their growth. As a rule, according to my 

 experience, they prefer slowly-running, or still water, to swiftly- 

 running streams. In very winding, and swiftly-running streams, the 

 current is comparatively slow at the outer edge of the curve; in such 

 places I have found good specimens. Their appearance under the best 

 conditions, is not unlike the domestic sponge, though at other times 

 they take on various hues of buff, and also of green. In some 

 species the statoblasts are abundant as early as the latter end of 

 June, while other species are not fully supplied with them till 

 October and November. In the earlier summer months, they fre- 

 quently spread out on the undersides of stones almost like fine net 

 work, becoming thicker as they grow older. They are at all times 

 beautiful and instructive objects under the microscope, and reward 

 the careful student of their peculiarities, equally with any objects of 

 natural historv under the same conditions. 



NEW MEANS OF HANDLING SECTIONS OF TISSUE 

 FOR THE MICROSCOPE.* 



WALTER Y. COWL, M. D. 



1\ /TR. PRESIDENT. — Since the microtome was first used in the 

 -^*-*- practical pursuit of histology, and in fact ever since we 

 have been able to cut large and thin sections of tissue, a need has 

 been growing for some more delicate means of handling these very 

 fragile objects than the ordinary copper section-lifter and steel 

 needle. 



And this need has considerably increased since the perfection 

 of those methods of freezing sj^ecimens, whereby comparative 

 homogeneity is attained in the mass and sections of extreme tenacity 

 secured from soft or even fresh tissue. 



*A paper read before the New York Society for Medico-Scientific Investigation. 



