228 IVAN E. WALLIN 
This criticism deals with the fragility of mitochondria. I have 
answered this criticism above. However, I again insist that even 
if such a difference were a reality, it, has no bearing on the problem. 
It must be admitted, on the basis of known biological behavior, 
that fragility is an accompaniment to well-established symbiosis and 
parasitism. 
2. Bacteria are stained like mitochondria by Regaud’s method. 
Portier’s ‘symbiotes’ resist alcohol and acetic acid, are stained easily 
without change after fixation. Guilliermond states that this fact is an 
excellent means of differentiating between mitochondria and ‘symbiotes.’ 
Guilliermond admits that some mitochondria are more resistant than 
others to acetic acid and alcohol, but maintains that the more resistant 
forms are no longer mitochondria, but plastids differentiated from 
mitochondria. 
In the first section of this paper I have shown that bacteria are stained 
like mitochondria by a number of mitochondrial methods, including the 
vital janus green method. From Guilhermond’s criticism it would 
appear that Portier’s ‘symbiotes’ are not mitochondria, but some other 
organism. In my work on staining of bacteria with mitochondrial 
methods I have found no fundamental difference in the staining reac- 
tions of mitochondria and bacteria. Guiliermond’s statement that the 
more resistant mitochondria are no longer mitochondria needs elucidat- 
ing evidence. If mitochondria metamorphose into organs that exhibit 
synthetic properties, then they assume properties that are characteris- 
tic of organisms. Numerous investigators have observed that mito- 
chondria differ in their power of resistance to acetic acid and alcohol. 
I have shown in the second section of this paper that bacteria also 
differ in their reactions to these chemicals. 
3. Mitochondria may be cultivated in certain cases. Guiliermond 
does not accept Portier’s statement that he has grown mitochondria. 
He concludes with the statement: “We cannot conceive that anyone 
can culture such fragile elements.”’ 
I am not in a position to intelligently consider this latter criticism 
at this time. On the basis of evidence that I shall submit in a paper 
in preparation, I feel confident that mitochondria may be transferred 
intact to culture media. While it must be admitted that a demonstra- 
tion of mitochondria growing as independent organisms in a culture 
medium would be absolute proof of their organized or bacterial nature, 
the lack of such a demonstration is not proof that they are cytoplasmic 
organs and not organisms. 
The writer will discuss Regaud’s and Guilliermond’s criticisms at 
_~more length in a paper in preparation. From the preceding discussion, 
it is apparent that the fundamental aspects of the problem are not 
clearly defined. This confusion is apparently due to the vagueness 
of mitochondrial and bacterial definitions. Mitochondrial literature 
has not supplied a satisfactory definition of mitochondria. Jordan’s 
“General Bacteriology”? does not contain a definition of bacteria. 
