n figure 2, and a small plug of filter-paper pulp was firmly pressed 
into the neck of the capillary tube (c) at (a). The wide part of the 
tube was then filled with water, which was forced through the 
plug (a) by means of a cyclepump attached by pressure tubing to 

the wide end of (6). Moderate pressure was all that was needed 
and the plug was firmly fitted into the neck of the capillary tube 
by the time the water in (9) had been driven through it. 
A small amount of the fluid to be tested was then placed in (0) 
and forced through the filter plug in the same manner, driving the 
water in tube (c) before it. On emerging from (c) the filtrate was 
collected in another capillary tube and was then available for 
further testing. 
Properties of the fluid. — The fluid when first exuded 1s ofa 
clear reddish-brown colour, perfectly mobile, and mixible without 
change with small quantities of water. It has a somewhat bitter 
taste, but no smell and gave with litmus an alkaline reaction. 
Small living tadpoles placed in it for some hours showed no signs of 
distress, and therefore to them at any rate it is non-toxic. This fluid 
contains proteins, pigments, inorganic salts, and other constituents. 
A full determination of these was impossible owing to the small 
quantity secretion obtainable. 
