THE BACTERIAL NATURE OF MITOCHONDRIA 27 



chondria in the smears were distinctly stained by these 

 methods. Gram's stain, however, did not bring them out as 

 sharply as the other methods. 



These two sets of staining experiments further indicate 

 the danger of attributing specificity to staining reactions. 

 These results do not behttle the value of various stains, 

 but they indicate rather the limitations of staining reactions 

 in determining the chemical constitution of small bodies that 

 cannot be isolated for direct chemical analysis. 



Chemical reactions. A number of investigators have 

 observed that mitochondria are sensitive to certain 

 chemicals. These chemicals are ether, alcohol, and acetic 

 acid. Two of them are used extensively in histological 

 technique, and this circumstance, perhaps, explains why 

 mitochondria were not recognized at a much earher date. 

 It is usually stated that these chemicals dissolve mito- 

 chondria. This may not necessarily be the case, for the 

 "dissolution" is usually determined by staining reactions. 

 It is obvious that the reagent may alter these bodies so that 

 they do not stain, and consequently they would not be 

 readily detected in the cytoplasm. 



The effects of alcohol, ether and acetic acid on bacteria 

 have been determined. Various strains of bacteria were 

 placed in shallow cups built up on microscopic shdes, and the 

 various solutions of acetic acid and alcohol were then in- 

 troduced. Ether was used in concentrated form. The 

 chemicals were allowed to remain for a time and then evap- 

 orated, leaving all solid matter on the slide. After floating 

 a thin layer of celloidin over the slide and permitting it to 

 harden, the preparations were stained. Microscopic ex- 

 ajnination of these preparations showed a variety of reactions 

 of the various strains of bacteria in the different solutions. 

 In some cases, the organisms remained intact, but were 

 unstained. In some instances, an amorphous mass is all 

 that remained on the slide; it was stained in some specimens, 



