92 
Mottier.—Chondriosomes and the Primordia 
and, since others may decide to use the processes followed by me, it may 
be worth while to give a somewhat detailed statement of the methods 
employed. 
Different killing fluids were used at first in fixing material, but the 
following proved to be so much more satisfactory for the tissues studied 
that it was finally employed exclusively: 
1 per cent, chromic acid . . . . . 17 c.c. 
2 per cent, osmic acid ..... 3 c.c. 
Glacial acetic acid ...... 3 drops. 
In many instances the glacial acetic acid was omitted altogether, although 
the cell contents, especially the nucleus, seemed to be brought out more 
clearly and definitely with the small quantity of the acetic acid. No satis¬ 
factory results were obtained when the amount of acetic acid in the above 
mixture was increased to one cubic centimetre. It is seen that one of the best 
combinations of these three acids used in fixing cells for the study of nuclear 
phenomena is quite unsatisfactory for the demonstration of chondriosomes. 
While the fixing of nuclei with the above mixture gave good results for 
some tissues, yet, in others, the details were not so well brought out. This 
was especially noticeable with nuclei in the resting condition. Less difference 
was observed in mitotic stages. 
In the literature one finds listed reagents which are suitable for 
chondriosomes, and others in which these bodies are dissolved. In some 
cases the statements of different writers seem to be contradictory. It is not 
easy to understand this unless the different authors refer to different 
structures under the same name ; or it is probable that the killing reagent 
which would preserve these bodies in one plant would dissolve them in 
another or render them incapable of being stained. I am inclined to 
believe from my experience, although I have not been able to test the 
matter thoroughly, that in some plants the bodies that may reasonably be 
placed in the category of chondriosomes are not injured by the amount 
of acetic acid contained in the chromo-osmo-acetic mixture used in the 
study of nuclear phenomena. 
Specimens were allowed to remain in the fixing fluid from thirty-six 
to forty-eight hours. After fixation the procedure varied with the method 
of staining to be employed. In all tissues studied by me two methods 
of staining were followed, the one used as a check upon the other, and in 
all cases the results were essentially the same. These two staining processes 
consisted, respectively, of a modification of Benda’s crystal violet, and the 
well-known iron-alum-haematoxylin stain. 
