Chondriosomes (M itochondria) and their Significance, i 
also seems little doubt that in some cases nuclear matter is extruded 
into the cytoplasm in the form of “chromidia.” Many earlier 
observations were also recalled in which various writers had des¬ 
cribed and figured granular or filamentous bodies in the cytoplasm 
of vegetable cells which might or might not he regarded as chondrio- 
somes— e.g., the chondriosome-like bodies found by Mikosch (1894) in 
epidermis and parenchyma cells of Sedum, Sempervivnm and Malvn, 
scattered in the cytoplasm or associated with the nucleus and the 
plastids though apparently quite distinct from either; by Schniewind- 
Thies (1897) in the septal nectaries of Liliaceae and Amaryllidaceae; 
by Bouin (1898) in the embryo-sac of various Liliaceae; and so on. 
Lundegard’s View of Plant Chondriosomes as 
Deformed Plastids. 
Lundegard (1910) worked with root-tips of Vicia faba , fixed 
with strong Flemming and stained with haematoxylin, and in his 
study of nuclear and cell-division in the apical meristem found that 
the cells invariably showed chondriosome-like structures in the 
cytoplasm. He then fixed entire roots before cutting off the root- 
tip, in order to eliminate changes in the cells attributable to wound 
reaction ; he dipped them for ten to thirty seconds in 1 % chromic 
acid, cut off the tips and placed them in weak Flemming, and 
stained the sections with iron haematoxylin or gentian violet. The 
same granular, vesicular and especially filamentous bodies were 
observed in the cytoplasm, chiefly around the nucleus. Next he cut 
longitudinal sections of living roots, which showed in the dermatogen 
and periblem numerous leucoplasts, mostly scattered in the cyto¬ 
plasm hut sometimes aggregated around the nucleus; and on adding 
to the sections various fixatives (strong and weak Flemming, iodine, 
chromic acid, etc.) found that the leucoplasts almost instantly 
showed changes in shape and position. These consisted usually in 
aggregation around the nucleus of previously scattered leucoplasts, 
but the latter frequently broke up into small portions which formed 
either scattered aggregates or moniliform filaments ; these changes 
Lundegard compared with the phenomena of systrophe or balling 
undergone by chromatophores as the result of various stimuli 
(changes in illumination, etc.) and long ago described by Schimper 
and others. Various other structures were formed which differed 
in form according to the fixative and stain employed, and these bore 
a striking resemblance to the various forms of chondriosomes; 
moreover, according to the strength of the fixative and the time 
during which it was allowed to act on the cells, every stage was 
obtained between normal leucoplasts and the variously deformed 
and chondriosome-like ones. Lundegard therefore concluded that 
part at any rate of the structures described as vegetable chondrio¬ 
somes are simply by the action of fixatives, plastids deformed and 
in this sense mere artefacts. 
Discovery of the Origin of Plastids from Chondriosomes. 
Almost simultaneously with this critical work of Lundegard’s 
there appeared in 1910 a paper by Lewitsky and another by Pensa 
which opened a new chapter in the investigation of plant chondrio¬ 
somes. Lewitsky (1910) studied various tissues of Pisum and 
Asparagus, using various fixatives, and in all cases obtained the same 
results: the cytoplasm contains filamentous and granular chondrio- 
