27 
N 
4. ISoiiie of contents ot" same reL-tuin i)lcif(Ml in -r-^Kl, and 
^ 40 
left for half an hour. Tested with ten two-volt storage cells. 
Opalina and species B, both to kathode. After half an hour 
still at kathode, where they had formed a small cluster. 
Thus the results of these experiments on galvanotaxis in 
different media also go to support the theory I have put for- 
ward. In addition, it may be mentioned that the results of 
Dale's experiments in galvanotaxis go generally to support 
this theory.* Thus, Balantidiuni duodenl shaken into solu- 
tions of increasing acidity collected closely at the kathode when 
the solution contained '02 per cent. HCl, the current being 
six pint bichromate cells. The same species in pure '6 per 
cent. NaCl went to anode with moderate currents, and to 
kathode with twelve cells. The latter result I believe to be 
due to the acid liberated at the anode causing the organisms 
to become ''positive." Dale also found that OpalnKi in '6 per 
cent, saline and '01 per cent. NaOH collected at the anode, 
and that X ijcfoflienix did the same when left in the solution 
for a sufficient time (ten minutes), and other instances, in 
which he used only specified inorganic solutions, will be 
noticed on referring to Dale's paper. 
4. The Structure of Striated Muscle. 
The following is extracted from Schafer's 'Essentials of 
Histology," sixth edition, page 102 : — "The sarcostyles are sub- 
divided at regular intervals by thin transverse disks (mem- 
branes of Krause) into successive portions, which may be term- 
ed sarcomeres ; each sarcomere is occupied by a portion of the 
dark stria of the whole fibre (sarcous element). The sarcous 
element is reaily double, and in the stretched fibre separates 
into two at the line of Hensen. At either end of the sarcous 
element is a clear substance (probably fluid or semi-fluid), 
separating it from the membrane of Krause. This clear sub- 
stance is more e\iclent the more the fibril is extended, but 
diminishes to complete c'isappearance in the contracted muscle. 
The cause of the change is explained when we study more 
minutely the structure of the saicous element. For each sar- 
cous element is pervaded with longitudinal canals or pores, 
which are open in the direction of Krause's membrane, but 
closed at the middle of the sarcous element. In the con- 
tracted muscle the clear part of the muscle substance has 
disappeared from view, but the sarcous element is swollen and 
the sarcomere is thus shortened ; in the uncontracted muscle. 
* H. H. Dale: Galvanotaxis and Chemotaxis of Ciliat-e 
Infusoria. Journal of Physiolog^v, 1901, page 291. 
