72 



Scientific Proceedings (126) 



4. Drain off the excess iodine solution, without blotting 

 (no water being used) but the film is not permitted to become dry. 



5. Add acetone (100 per cent.) drop by drop until no color 

 is seen in the drippings from the slide, which is slightly tilted. 

 This usually requires less than 10 seconds, and should be reduced 

 to a minimum. 



6. Air dry the slide. 



7. Counter stain for 10-30 seconds with 0.1 per cent, aqueous 

 solution of basic fuchsin. 



8. Wash off excess stain by short exposure to tap water and 

 air dry. If slide is not dear, immersion in xylol is recommended. 



This method has yielded particularly good results in staining 

 milk slides for Bacillus Acidophilus and in staining fecal speci- 

 mens. By this method gonococci and diphtheria bacilli are 

 particularly well differentiated and more easily identified than 

 by the older methods. The same was found to be true for a 

 number of common pathogens and saprophytes studied. 



34 (1994) 



Permeability of the cell: the surface as contrasted with the 



interior. 



By ROBERT CHAMBERS. 



[From the Department of Anatomy, Cornell University Medical 

 College, New York City.] 



Protoplasm is known to he permeable to some substances and 

 not to others. The microinjection method appears to be the only 

 method of determining whether this semi-permeability is a 

 property of the entire mass of protoplasm or of its surface film 

 only. 



