6 PROCEEDINGS OF THE ACADEMY OF [Jan., 



results not far short of the best slide staining. The use of counter- 

 stains in alcohol is a great time-saving device, since the preparation 

 has but to be passed from xylol, to absolute alcohol, to 95 per cent, 

 alcohol, to the stain and back again to be ready for the Canada bal- 

 sam. Moreover, if acid fuchsin be used, one quick dip in the stain is 

 sufficient. 



For slide staining, iron hsematoxylin, Wright's and Giemsa stains 

 and thionin were used either with or without counterstains. The 

 blood stains used alone are unsatisfactory, since only the blue ingre- 

 dients seem to take hold of the tissues. Wright's stain, counter- 

 stained with alcoholic eosin, however, gave very good results. The 

 technique was as follows: The slide holding the sections was first 

 treated as a blood smear and allowed to lie with the mixture of 

 stain and water upon it for 10 to 15 minutes. It was then washed 

 first in water and then in 95 per cent, alcohol until all of the pre- 

 cipitated stain had dissolved. It was then stained with eosin dis- 

 solved in absolute alcohol, next passed into clean absolute alcohol, 

 and finally into xylol. Wright's stain comes out very rapidly in 

 alcohol, but the whole procedure as above outlined can be completed 

 in a very short time. 



Thionin preparations counterstained in either alcoholic eosin or 

 acid fuchsin in alcohol were largely used and gave in some respects 

 the best results. Preparations so stained display beautifully sharp 

 and clear-cut pictures, and they are very good when it is a question 

 of bringing out the chemical qualities of different parts of the para- 

 sites. On the other hand, thionin fails to bring out certain granules 

 in these Sarcosporidia which are perhaps significant, and slides 

 stained in thionin are not permanent. 



Accordingly, most of the slides were stained with iron hsematoxylin. 

 With material fixed in Hermann's fluid, a counterstain is not neces- 

 sary, although it was often used. With the other fixatives a 

 counterstain was necessary, and acid fuchsin was the one most 

 generally employed. 



The list of mice used follows: 



Mouse 77 15 hours. 



99 3 and 6 hours. 



106 ... 9hours A. C. A Heavymeal. 



120 . 10i and 17 hours Heavymeal. 



121 10| and 17 hours Heavymeal. 



L25 2J hours Hermann's fluid. 



128 3f hours Picro-acetic. 



132 .... 8J hours Hermann's fluid Heavymeal. 



133 9 hours Hermann's fluid Heavy meal. 



145 llfhours Hermann's fluid Moderate meal. 



