44 
The Ohio Naturalist. 
[Vol. VII, No. 3, 
dum* Farmer and MooreJ also consider that in the second 
karyokinesis we have a continuation of the longitudinal splitting 
begun during the first. We have thus a rational explanation of 
the observed facts—an explanation as to why when pseudo¬ 
reduction and qualitative reduction take place these processes 
are so generally followed by a second karyokinesis. 
Accepting McClung’s term, synizesis, for the massing or 
contraction of the chromatin in the prophase of division, the 
question remains to be settled as to whether this is a normal or an 
artificial production. Two methods seem available for the solu¬ 
tion of this problem. One may stud}' the effects of plasmolizing 
reagents on known structures and make comparisons or else one 
may attempt to study the stages in question from the living 
material. 
In 1899J I found that a violent distortion of the chromatin 
and the so-called sickle stage of the nucleolus may be produced 
even in resting cells of the root tips of onions by using a violent 
killing fluid. This fluid was made according to the following 
formula: 
Absolute Alcohol.95 cc. 
Chloroform. 5 cc. 
Glacial Acetic Acid. 1 cc. 
Chromic Acid (8% H 2 0 Solution). 1 cc. 
The combination proved to have a very bad effect as a kill¬ 
ing reagent and was simply one of many tried in a series of exper¬ 
iments. Figures 5 and 6 represent cell rows from opposite sides 
of a section of onion root tip (Allium cepa) killed in this 
fluid. Nearly all of the nuclei of the peripheral cells showed 
decided distortions. The nuclei are crowded toward the outer 
walls of the cells, while the nucleoli are generally pushed in the 
opposite direction. The chromatin and other dark-staining 
material is also massed to some extent on the inner side of the 
nucleus. In the central strands there is little displacement al- 
through the cells are shrunken. No such distortions are ever to 
be seen in properly killed root tips and especially is there no such 
symmetrical arrangement of the nuclei and nucleoli in the outer 
layers of cells. This appearance then is purely on artifact which 
may be of assistance in the interpretation of other cases. In 
judging of synizetic contractions, it is also important to take 
into account the probable expansion of the nuclear cavity. The 
* -. A Contribution to the Life-history and Cyto¬ 
logy of Ervthronium. Bot. Gaz. 31 : 369—387, 1901. 
f Farmer, J. B., and Moore, J. E. S. On the Maiotic Phase (Re¬ 
duction Divisions) in Animals and Plants. Quar. Jour. Mic. Sci. 48 : 489- 
551, 1905. 
JSchaffxer, John' H. Artificial Production of the Sickle Stage of 
the Nucleolus. Jour. App. Micr. 2 : 321-322. 
