Physiology. 371 
On the other hand, Valentin, by the use of the balance, observed 
an increase in weight of about y4,, during tetanus. 
Other observers have obtained results quite as contradictory, and 
it seems almost as if every investigator came to conclusions differ- 
ing from those reached by his immediate predecessors. All the 
while, however, the balance of evidence has appeared to be on the 
side of those who claimed that there was a slight decrease in the 
volume of the contracting muscle. Most of the recent text-books 
state it as probable that there is this minute diminution in volume. 
ere has recently been published an important paper on the 
subject by Professor J. R. Ewald,! who has repeated, as closely as 
possible, the experiments of Erman, Marchand, Weber and Valen- 
tin. Ewald regards Erman’s method as by far the most delicate, if 
conducted in the right way and under favorable conditions. He 
then suggests that Erman and ‘his successors have erred in some 
critical respects in the course of their experimental work. 
Ewald accordingly altered Erman’s method in the following 
manner: Into a glass flask two platinum wires are melted just 
above the base, so that they are diametrically opposite, and reach 
some millimetres down into the vessel. On the outside they form 
small hooks upon which can be hung the wires leading to an induc- 
tion machine. The glass stopper of the flask is hollow and ends 
in a tube which is drawn out so as to be capillary. 
The animal is killed under water, and the muscle without the 
nerve freed from the body. The flask, stopper and capillary tube 
to sink with great swiftness, owing to the expansion of the glass. 
A drop of ether evaporated on a lass anion the reverse effect 
>the meniscus rapidly rises. If the strength of the current be 
d so that bubbles of gas begin to be formed on the elec- 
trodes, it will then be seen whether a very slight increase of vol- 
ume in the interior of the flask will perceptibly change the posi- 
1 
Pe Md (Pfliiger’s) fiir die gesammte Physiologie (1887), Bd. xli., 8. 
