246 Papers from the Department of Marine Biology. 
cells, as a centrifugal force, in directions at right angles to the dorso- 
ventral direction and also in the ventro-dorsal direction or the reverse 
of the natural pull of gravity. In practically all cases the proper 
controls were secured and it soon became apparent that this force 
might be the main cause of the orientation. By referring to the table 
it will be seen that 5 experiments were performed on torpedoes Nos. 8, 
9, 3, 20, and 4. Also, it can be seen that the forces applied to the 
tissues were, in terms of gravity, for torpedo No. 8, 1 time gravity in 
reverse direction to nature for 8 days; for torpedo No. 9, 40.6 times 
gravity for 2 minutes at right angles to force of gravity in nature; for 
torpedo No. 3, 543 times gravity for 2 minutes at right angles to 
gravity in nature; for torpedo No. 20, 601 times gravity in reverse 
direction to nature for 30 minutes; for torpedo No. 4, 828 times gravity 
at right angles to nature for 30 minutes. 
Thus we have a series of 5 experiments ranging from the natural 
force of gravity reversed and applied for 8 days up to 828 times gravity 
applied for 30 minutes. 
The first experiment of this series, on torpedo No. 8, yielded no 
visible results. In this case we had a small fish to deal with, which 
somewhat lessens the value of the experiment. No orientation ap- 
peared in the brain as a result. Thus the questions are left open: 
Did any orientation exist in a ventral direction which had been nullified 
by the experiment? And, would a result have appeared if the fish 
were larger and had possessed a natural orientation? Another experi- 
ment of this nature should have been tried on a larger fish, but the 
two questions can. still be answered, I think: the first by the state- 
ment that all small fish possess no orientation, or very little, and the 
second by a similar experiment performed on an adult T'etronarce occi- 
dentalis, to be described in another paper, in which the plasmosomes are 
always oriented sharply in the ventral position. The same experiment 
performed on this large fish showed that gravity alone could not move 
the plasmosome in 7 days in this adult form. 
Turning to experiments on torpedo No. 9, we find that we are dealing 
with a 16 cm. fish, which is small, but not as small as torpedo No. 8. 
The control made in this case shows that a considerable amount of 
natural orientation was present, about 15 per cent.. The force applied 
as a centrifugal force by the centrifuge was low compared to the later 
experiments, but high compared to gravity, being a little over 40 times 
that measure. The time was 2 minutes and perhaps should have been 
longer to show a complete negation; still, since some of the later 
experiments with stronger forces were also of short duration, we can 
feel satisfied that real results are being secured and real comparisons 
being made. The results in this example were completely negative, 
showing that when 40 times the force of gravity is applied for 2 minutes 
the contents of the nucleus remain undisturbed. 
