ON THE NATURE OF MITOCHONDRIA Del 
The effect of janus green on tubercle bacilli was contrary to 
expectation. On account of the fatty envelope of these forms, 
it was to be expected that they might stain more intensely than 
any other bacteria. This would imply that fats, waxes, and 
lipoids should respond in a like manner to a given stain. Such 
an inference may not necessarily be true. However, the proof 
that mitochondria are of a lipoidal nature is far from conclusive. 
While there is nothing specially indicated as to the chemical 
nature of the bacteria that were stained by janus green, it would 
appear that one is justified in concluding that these bacteria 
and mitochondria do have something in their chemical structure 
that is common to all. 
The different reactions of a strain of bacteria at different 
periods in the life of the culture to janus green is suggestive. 
It would appear that janus green has possibilities as a deli- 
cate indicator of the physiological state of certain strains of 
bacteria. 
II. REACTIONS OF BACTERIA TO CHEMICAL TREATMENT 
The behavior of mitochondria when subjected to various chemi- 
cals and heat has been one of the chief methods used in determin- 
ing the nature of these bodies. N. H. Cowdry (717) made 
a detailed study of the comparison of mitochondria in plant and 
animal cells. The behavior of the two groups of mitochondria 
under the influence of various chemicals (ether, alcohol, for- 
maldehyde and acetic acid) as well as their morphology was the 
method employed in this comparative study. Cowdry concludes 
that there is no difference between the mitochondria of plants and 
animals. 
It must be admitted at the outset that in most instances there 
is nothing specifically indicated in the reaction of minute micro- 
scopic particles to chemicals. With perhaps a few exceptions, 
these reactions are only relative. For example, ether acting upon 
tubercle bacilli for a limited time will extract a fat (supposedly 
forming an envelope for the bacillus) from the organism. From 
such a reaction there is nothing indicated as to the particular 
kind of fat that has been dissolved. However, inasmuch as these 
