618 DR A. ANSTRUTHER LAWSON ON 
anaphase, where they become massed together, or during the act of reduction, when they 
unite in pairs. ‘There are other times when they seem to be repelled from one another, 
as, for instance, at the close of the prophase, as shown in fig. 24, or in the present case, 
when they move to opposite sides of the cell. Here the idea of electrical conditions 
suggests itself as a plausible explanation, Without underestimating the value of this 
idea, the evidence in support of it is as yet not of a highly convincing nature. That 
electrical energy is generated in the cell is no doubt quite true, and it would seem not 
improbable that it plays a réle in the attraction and repulsion of the chromosomes. 
But the idea of chemotactic conditions should not be overlooked in this matter. 
THe ANAPHASE. 
The two groups of chromosomes are now at opposite ends of the cell, with numerous 
drawn-out threads of cytoplasm stretching between them. There is no doubt in my 
mind that these threads represent the same state of tension expressed in the achromatic 
figure of the Jater prophase and metaphase. ‘The lines of tension have merely shifted 
with the movement of the chromosomes. As shown in figs. 37 and 38, the individual 
chromosomes of each group become closely massed together. It may be worthy of 
note that the union here is a close and intimate one, as may be seen in fig. 38. There 
now begins an accumulation of karyolymph within the chromosomes. This appears 
first as minute lacunze, which become larger and give the chromosomes a vacuolated 
appearance. In Aloe, where the chromosomes are much larger than those in Smlacina, 
the vacuolation and the accumulation of karyolymph could be followed with great 
clearness. The progressive steps in this process were so exceptionally evident in Aloe, 
that I have thought it worth while to illustrate them in figs. 58, 54, 55, 56, and 57. 
These figures, along with that of fig. 39, convincingly prove that throughout the three 
changes the general contour of the individual chromosomes is never lost. ‘The accumula- 
tion of the karyolymphis fairly rapid, and it soon extends beyond the chromosomes and 
comes in contact with the cytoplasm. The formation of a membrane about each 
daughter nucleus, as a result of this contact, is shown in figs. 39, 56, and 57 (Lawson, 
1904). 
As the daughter nuclei continue to increase in size, the cytoplasmic fibrils stretching 
between them become curved, as if the tension were being relaxed. This is indicated 
in fig. 39. This curvation of the fibrils continues until the combined volumes of the 
daughter nuclei approximate that of the mother nucleus (fig. 24), when the tension 
becomes completely relaxed and the fibrils are no longer visible as such. In the 
meantime a thin cell wall is laid down midway between the nuclei, as shown in 
fig. 40. 
Tue Seconp Metoric Drvistron. 
In order to avoid repetition of unessential details, I shall not attempt to follow 
through the second meiotic division as closely as I have done the first. I shall merely - 
