^{page 220 note *} Mr Günther suggested that bacteria were already present in the waters. This, however, appears improbable; for it was found that, after the india-rubber tubes had been purified and the use of vaseline discarded, another portion of the water with which the tubes were charged when much trouble had been experienced, could be kept in the apparatus for three or four weeks without producing any ill effects ; micrometer readings taken at various times during that period were always normal.

It may also be added that, although the author has examined many hundreds of samples of sea-water, he has never observed the development of any similar oiliness within the containing bottles.

^{page 225 note *} Challenger Reports, vol. i., part 2, p. 1.

^{page 231 note *} Phil. Trans., vol. A, 1893, p. 435.

^{page 231 note †} Proc. Roy. Soc. Edin., 1903, p. 356

^{page 232 note *} For the continued loan of this pipette, I have to thank Dr Dickson.