and Laboratory Methods. 2413 



healthy and in good condition at the end of that time. The cloth needs chang- 

 ing or washing once in two weeks, or oftener, otherwise bacteria and fungi may 

 get a foothold, destroying the worms. Possibly more specimens could have 

 been kept in a single dish ; with a larger vessel this would certainly be the case. 

 The specimens are accessible at any time ; the cover may be removed and one 

 or more worms taken at any moment. The dishes were kept in the light, on 

 the laboratory tables. This method would furnish excellent facilities for ex- 

 perimentation or continued observation of the worms ; they may be fed on 

 leaves, etc., if desired, and a given individual may be examined repeatedly 

 whenever desired. 



The method described above was devised by Joest for cleaning out the in- 

 testine of the worms preparatory to sectioning. For this purpose it seems to 

 the writer much superior to any other. The worms cannot devour the cloth, 

 but continue to void the waste matter, so in the course of a few days the in- 

 testine becomes entirely empty. The method is therefore much better than 

 those in which the intestine becomes filled with paper pulp, bread, coffee 

 grounds, or the like, which often cause serious difficulties in the sectioning. In 

 order to insure the thorough cleaning of the intestine, the cloth should be 

 changed every day, so that the worms may not again ingest the voided sand, 

 dirt, etc. It is usually not difiicult to tell by inspection when the worms have 

 become entirely clean and empty. H. S. Jennings. 



University of Michigan. 



Soluble Glass as a Satisfactory Mounting Medium. 



Having occasion to make frequent examinations of paper, and to prepare 

 reference mounts of the fibers composing the sample, I have found soluble glass 

 a mounting medium allowing of rapid and satisfactory work. 



The paper under examination is softened by soaking in warm distilled water, 

 and worked with the hand until reduced to a light pulp. A portion of this is 

 then taken, and with the assistance of a low power lens and a pair of teasing 

 needles, arranged on a slide. 



The surplus water must now be removed, and the slide is, therefore, held 

 over a flame until just sufficient liquid remains to wet the preparation evenly. 

 The evaporating should be done carefully, so that bubbles will not be formed. 



A drop of a thick soluble glass solution is then placed on the fibers, and a 

 cover-glass laid on in the usual manner. The film of moisture, which is depos- 

 ited by condensation on the cover-glass as it is lowered, is, to a great extent, 

 the remedy for the numerous air bubbles, which, because of the uneven spread- 

 ing of the soluble glass, would be formed were a dry cover-glass used, and which 

 the rapid hardening of the medium would render impossible to remove. 



The advantages of this method are: simplicity; durability of the prepara- 

 tions (provided they are kept from fumes of HCl) as indicated by about two 

 years' use in the laboratory; infusibility of the medium, allowing of projection 

 with any kind of illumination, and for as long a time as desired; greater dis- 



