F. F. Blackman. 
n 
produce an enormous effect. The best theory of their action is 
that they form intermediate compounds with the substances to be 
changed. Thus the Pt. first unites with the 0 2 and the oxide then 
reacts with the FL to form water, regenerating the Pt. For the 
Pt. to have this accelerating katalytic action it must happen that 
Pt, reacts quicker with Oo and the oxide reacts quicker with H,, 
than oxygen would unite directly with hydrogen. Of course a 
katalyst cannot supply energy, and no energy is required to unite 
H 2 and 0 2 , but on the contrary latent energy is liberated, so that 
the katalytic agent has quite an easy and almost accidental function 
which it can continue indefinitely. 
In thus accelerating the reaction the katalyst produces just the 
same effect as an increase of temperature would. Striking as it 
is to see hydrogen aud oxygen uniting rapidly at the ordinary 
temperature instead of requiring 500 n C, yet there is nothing 
mysterious about it, and it is only that a naturally slow reaction is 
enabled to go on as fast as do so many ordinary reactions (say HC1 
on Na„C0 3 ) without any intervening katalytic substance. 
Now it is instructive to recall that this power of carrying on at 
low temperatures reactions which require a high temperature to go 
by themselves, has long been regarded as the mysterious prerogative 
of protoplasm. The explanation is then clearly this, that protoplasm 
is a complicated congeries of katalytic agents, adapted to the 
metabolic work that the cell has to do. 
These protoplasmic katalysts are grouped together as enzymes. 
They are indiffusible colloids, probably proteid in nature, of 
varying degrees of simplicity and stability and either naturally free 
in the reticula of the protoplasm or forming hypothetical “enzyme- 
branches of the protoplasm.” Every year new ones are isolated, 
and it would seem that there may well be one for every change the 
cell conducts that is not naturally capable of proceeding rapidly at 
the vital temperatures. 
In 1897 Buchner, by the quite new method of expressing the 
liquid contents from living cells, succeeded in preparing the 
katalytic agent (zymase) of the last outstanding fermentation- 
process, the alcoholic fermentation of sugar by yeast. Thus was 
swept away a vitalistic barrier that many thought would last for all 
time and a large region of vitality has become the “ Hinterland ” 
of pure chemistry. 
Progress along Buchner’s lines soon showed that it was not 
necessary to break up the yeast-cells in order to get alcoholic 
