10 THE MICROSCOPE. May 



remedies, but ou a plane below, ofteu far below, the first 

 claim and initial hope. Is it to be thus with Formalde- 

 hyde as an antiseptic, as remedial agent, as preservative, 

 as a histological fixative ? It can only find its true plane 

 among its kind by conscientious trials made and reported 

 by investigators. During the last year it has been used 

 in the laboratory of the Ohio State University quite ex- 

 tensively as a preservative and for histological purposes. 

 I have brought together in this paper the results and the 

 reflections to which they obviously lead. Papers have 

 appeared in the last year or two giving results from lab- 

 oratories along similar lines. I may say at the outset that 

 my experience leads to conclusions essentially in accord 

 with results heretofore published. 



In the statement of trials I shall by "per cent" mean 

 per cent .by volume of the forty per cent solution of for- 

 maldehyde in water, procured of Sharing & GlatzofNew 

 York, and distilled water. I have found this standard 

 solution known as formalin fairly constant, and so a re- 

 liable solution may be thus quickly made of pretty con- 

 stant strength. 



I. As a preservative I have tried it on a variety ol 

 objects, using varying strengths with results to be noted. 



Experituent 1. Small sunfish perfectly fresh was put 

 into two per cent formalin Feb. 2 ; March 1 it was well 

 hardened without shrinkage; colors fairly preserved 

 compared with the best alcoholic specimens ; eyes better; 

 fins extended. The fluid was filtered, the bottle sealed 

 and given a place on the shelf. July 1, no perceptible 

 change observed. 



Experiment 2. Two common eels from the market were 

 immersed in four per cent March 11. July 1, examina- 

 tion showed that they were in perfect condition as to 

 color, absence of shrinkage and firmness. The fluid had 

 colored slightly and there was a sediment. Filtering ren- 



