io8 Mottier.—Chondriosomes and the Primordia 
Discussion. 
A number of investigators (Guilliermond, Lewitsky, Rudolph, Foren- 
bacher, and others) are now agreed that, in the higher plants studied by 
them, both leucoplasts and chloroplasfs are developed from round or rod¬ 
shaped primordia which may be readily observed in meristematic tissues, 
either in the living state or after the application of certain definite fixing 
and staining procedures, and which have been referred to as chondriosomes. 
It is also to be inferred from the literature that leucoplasts and chloroplasts 
are morphologically the same—a conclusion substantiated by the facts. But 
as to whether these primordia of chloroplasts and leucoplasts are permanent 
organs of the cells, having morphological rank, there is doubtless much 
difference of opinion. A number of observers have confined themselves 
chiefly to these primordia, while others have mentioned, in some cases only 
incidentally, the presence of other bodies which do not develop into 
chloroplasts or leucoplasts. Forenbacher, who has described the transforma¬ 
tion of chloroplasts and leucoplasts from their primordia in the stem and root 
of Tradescantia , merely mentions the fact, without further comment, that 
other bodies are present in the cells, which are morphologically like 
chondriosomes ( 1911 , p. 658): * Es ist erwahnenswert, dass ich immer sowohl 
im Stengel wie in der Wurzel neben den schon entwickelten Chromatophoren 
noch Gebilde, die morphologisch mit den Chondriosomen vollkommen 
ubereinstimmen, vorfand.’ As to the morphological individuality of the 
primordia of leucoplasts and chloroplasts Forenbacher is non-committal 
( 1911 , p. 660). 
On the other hand, Rudolph ( 1912 ) and Sapehin ( 1913 ) distinguish 
between the primordia of plastids and other bodies that do not develop into 
either chloroplasts or leucoplasts. Rudolph is strongly inclined to the view 
that chondriosomes and the primordia of plastids are entirely different 
structures. In his summary ( 1912 , p. 626) he says that in the primary 
meristem of the growing point (speaking of the stem of Asparagus officinalis) 
there are present chiefly granules varying in size. Elongated forms are 
mixed in among them, occurring singly, but these may be regarded as 
division stages. Some of the granules increase rapidly in size, multiply, 
and change into chloroplasts and leucoplasts. The division stages are at 
times, even in older tissues, elongated so that the rod-shaped forms approach 
those which are filamentous in form with swollen ends. These are especially 
abundant in the elongated elements of the vascular bundles. However, all 
transitions to normal division stages are present. The remainder of the 
granules of the meristematic cells persist in their original form, multiply as 
the cells divide, and thus become distributed to all cells. Out of these are 
formed threads varying in length, which become more numerous as we leave 
the growing point. It is probable that the threads represent incompletely 
