Chondriosomes (Mitochondria) and their Significance i ^5 
has been seen, dissent from the chondriosome view of plastid origin, 
and if their conclusions be accepted it would appear that in 
Bryophyta as in Algae the Schimper-Meyer theory holds good, at 
any rate for the forms which have been fully investigated. As 
pointed out by Lotsy (1907, p. 27), the correctness or otherwise of 
the Schimper-Meyer view—according to which ehromatophore 
characters are transmitted only in the female line, the chromato- 
phores of the individual offspring being derived from those of the 
oosphere—might be tested experimentally if hybrids could be 
obtained between forms with markedly different chromatophores. 
As already mentioned, Schmidt regards the work of Pensa, 
Lewitsky, Forenbacher and Guillermond as merely confirming the 
Schimper-Meyer theory by applying methods which have made it 
possible to detect younger stages in the development of chromato¬ 
phores than could be observed with previous methods of fixation 
and staining. Similarly one might regard the work of these later 
investigators as reconciling with the Schimper-Meyer theory the 
statements of earlier observers who failed to find chromatophores 
in the oosphere or the embryo or young tissues, and who concluded 
that chromatophores arise de novo by differentiation of the proto¬ 
plasm simply because their technique did not enable them to see 
the earliest stages in the growth of these bodies; though, on the 
other hand, the upholders of the Pensa-Lewitsky view consider 
that the minute rod- or spindle-shaped bodies observed by Mikosch 
in living cells were chondriosomes. 
Apart from the three chief views put forward, namely, (1) that 
the chromatophores of higher plants arise de novo by some process of 
differentiation from the general cytoplasm, (2) that they arise from 
pre-existing chromatophores traceable throughout the life-cycle, 
and (3) that they arise by modification of special cytoplasmic 
structures or chondriosomes homologous with the similarly-named 
bodies in animal cells, two other theories have been put forward 
which have received little support. Mereschowski (1910) stands 
as yet alone with the somewhat remarkable theory that the 
chromatophores of plants, like the green cells found in various 
animals, are symbiotic organisms and represent green or blue-green 
Alg'e which originally entered the cell as endophytes and have now 
become symbionts or helots as in the case of the lichen thallus. 
Schiller (1909) adopted Goldschmidt’s chromidial theory and 
combined it with that of the existence in plants of two independent 
nuclei corresponding to the meganucleus and micronucleus of certain 
Protozoa, regarding the chromatophores as representing a mega¬ 
nucleus (Dotterkern) ; he could find no trace of plastids in resting 
embryos of Triticum and Phaseolus but thought they arose later 
from the nucleolus which passed out of the nucleus into the 
cytoplasm and there broke up into grains, these losing their stain- 
ability with iron haematoxylin as they developed into chromatophores. 
Chondriosomes and Myelin Forms. 
As already noted, Lundegard in 1910, just prior to the publication 
of the papers by Pensa and by Lewitsky which challenged the 
Schimper-Meyer theory and advocated the new view that chromato¬ 
phores arise from chondriosomes, published his results which led 
to the view that the so-called chondriosomes of plants are merely 
