2O2 



N. H. COWDRY. 



TABLE I Continued. 



No. 



Fixative. 



Radicle of Pea. 



Pancreatic Acini. 



1610 



i6nA. . 

 1612. . . . 



1613 



1614. . . . 



sat. aq. corrosive subli- +distinct, shrunken 



mate 

 sat. aq. picric acid 



2 % chromic acid 



3 % bichromate 



5%osmicacid 



+nearly normal 

 +somewhat distorted 

 +normal 



+unsatisfactory 



+few, indistinct 



+few, fragmented 

 +few, fragmented 

 +nodular rods, rings, 



granules 

 +normal 



by Sapehin ('15, p. 321). Formalin in combination with picric 

 acid is a somewhat erratic fixative, very excellent in some 

 instances and bad in others. In good preparations the mito- 

 chondria appear very large and not so shrunken as when acted 

 on by other fixatives. Formalin and chromic acid constitute a 

 poor fixative which fragments the mitochondria and, in some 

 cases, destroys them entirely. 



Potassium bichromate used alone (Sapehin, '15, p. 321) is a 

 good preservative for mitochondria but penetrates badly. Re- 

 gaud recommends its use in mixtures and as a mordant in 

 order to render the mitochondria insoluble in the alcohols during 

 dehydration. The bichromate which remains in the tissue when 

 it is sectioned, increases its affinity for fuchsin when the fuchsin 

 methyl green stain is applied. 



Ethyl alcohol in 95 per cent, solution destroys the mito- 

 chondria in both the pea radicle and the pancreas. When alcohol 

 is employed in gradually increasing concentration the same 

 result is obtained. When it is combined with potassium bichro- 

 mate the mitochondria are also destroyed. In fact our conclusion 

 can be none other than that alcohol, in whatever combination, 

 is a very poor fixative for mitochondria. 



Boiling water preserves the general form relations but does 

 not bring to light any mitochondria. 



Picric acid is a fairly good fixative for mitochondria in the 

 cells of the pea and pancreas, when used in a saturated aqueous 

 solution. It has the great advantage that it penetrates well. 



Chromic acid alone causes considerable distortion of the mito- 

 chondria and somewhat irregular coagulation of the ground 

 substance but in combination it is apparently very efficacious 

 as shown by its inclusion in Benda's modification of Flemming's 

 fluid and in other mixtures. 



