o5 
are the essential features of the constitution of the universe. 
The principles of one science reappear in all the others ; the 
study of any branch of natural philosophy results in 
generalisations which elucidate the phenomena of other 
branches. And if he turns from the physical side of nature 
to its moral side^ the thinker finds the lessons of the one 
applicable to the other, and confirmed by its phenomena. 
The recognition of this truth does not seem to me to be 
beyond the scope of science. Microbia have a beneficent 
function ; Pasteur’s pupil, Duclaux, has shown us that the 
seeds of the higher plants will apparently not germinate 
if microbia are excluded from the soil ; and Pasteur himself 
has suggested that probably no young animal would live if 
its food were absolutely deprived of organised ferments. 
The evidence tends to show us that if these same ferments 
are compelled to live in the environment provided by their 
individual action alone, they become the agents of deadly 
disease. If we turn to the other extreme of the biological 
chain we find that, with his physical nature deprived of 
sun-light and fresh air, and his mental nature compelled to 
feed upon its own vagaries, in short, with his mind darkened 
and unaerated, man himself becomes morbid and mischievous. 
“ On the Flow of Gases,” by Professor Osborne Eeynolds, 
LL.D., F.RS. 
1, Amongst the results of Mr. Wilde’s experiments on the 
flow of gas, one, to which attention is particularly called, is 
that when gas is flowing from a discharging vessel through 
an orifice into a receiving vessel, the rate at which the 
pressure falls in the discharging vessel is independent of 
the pressure in the receiving vessel until this becomes 
greater than about five-tenths the pressure in the discharging 
vessel. This fact is shown in tables IV. and V. in Mr. Wilde’s 
paper. Thus the fall of pressure from 135 lbs. (9 atmospheres) 
in the discharging vessel being 5 lbs. in 7*5 seconds for 
