A STUDY OF PLASTIDS AND MITOCHONDRIA 
231 
others to substantiate their contention that the Anlagen of the plastids are 
different from the mitochondria fail for the same reason — they are unable 
to demonstrate such a difference. Guilliermond ('14) claims that he is, in 
reality, upholding the Schimper-Meyer theory in that he is bridging a gap 
which the latter, with their cruder technique, were unable to fill. Schmidt 
('12) also maintains that the work of Guilliermond and others confirms the 
Schimper-Meyer theory, but for a very different reason : they have simply 
been demonstrating the earlier stages of the plastids, according to Schmidt. 
Lewitsky, however, claims to have shown that there are no other Anlagen 
of the chloroplasts than the mitochondria. His findings, with respect to 
Asparagus officinalis, which have already been referred to, are specifically 
as follows: a stem-tip of Asparagus officinalis was fixed with alcohol, 3 
parts, and acetic acid, i part. This was stained with iron-alum-haema- 
toxylin and light green. In the third and fourth cell-layers from above, 
where, in the preparations fixed by the Benda method, the somewhat large 
"chromatophore-dumb-bells " were found, these were no longer to be seen; 
only the usual " Plasmagertist'' was present. Since the mitochondria are 
destroyed by acetic acid and alcohol, and since all of the Anlagen, including 
the dumb-bell forms, disappear with the mi ochondria under fixation with a 
combination of the above named reagents, these facts are taken as conclusive 
evidence of the identity of the mitochondria with the Anlagen of the plastids. 
Conclusions 
My ow^n observations may be briefly summarized as follows: 
1. As to size, an unbroken series of bodies, from mitochondria to plastids, 
can be traced in the root-tip cells of Zea Mays from the embryonic region 
backward. In Preissia this sedation is not so obvious. 
2. The contention that such definitely staining bodies as the mitochon- 
dria exist and are normal constituents of the cytoplasm can hardly be 
questioned. 
3. The evidence for the division of the mitochondria as well as that for 
their functions in heredity seems to me to be inadequate. 
4. The further fundamental question as to the relation of the mitochon- 
dria to the remainder of the cytoplasm and the nature of the material in 
which they are imbedded, has not been cleared up. 
5. Red-staining bodies are present in the plastids of corn, and, in some 
cases, in those of Preissia also. 
BIBLIOGRAPHY 
Beer, R. 1905. On the development of the pollen grain and anther of some Onagraceae. 
Beih. Bot. Centralbl. 19: 286-311. 
Campbell, D. H. 1906. Multiple chromatophores in Anthoceros. Annals of Botany 20: 
322. 
Cavers, F. 1914. Chondriosomes (mitochondria) and their significance. New Phytol. 
13: 96-106; 170-180. 
Cowdry, N. H. 1917. A comparison of mitochondria in plant and animal cells. Biol. 
Bull. 33: 196-228. 
