Incipient Vitality. 2 7 
The burning question of the hour is whether this universal 
zymase really contributes the first stage of normal respiration ; 
whether, in the presence of oxygen also, sugar is normally split up 
to form alcohol and a certain amount of C0 2 , after which the 
alcohol is then further oxidised to water and more C0 2 . The 
latter stage would he presumably accelerated by an oxidising 
enzyme, an oxydase, and naturally would be suspended in the 
absence of available oxygen. Various oxydases are present in 
living cells, but no evidence of one accelerating the oxidation of 
alcohol has yet been obtained. 
The most recent contribution to this line of work has been 
made by Palladin. 1 He has made two important advances. He 
has shown that massive organs of the higher plants can be killed 
without destroying their various enzymes by the action of sudden 
intense cold, and that onion bulbs, for instance, on thawing after a 
short exposure to-20C, give out C0 2 for a period of many hours. 
This is due to the action of the same enzyme that works in yeast. 
This freezing method is much more suitable for dense impervious 
plant-organs than the use of alcohol and ether. 
Palladin has further shown that, with some plants, the enzyme 
does not come out into the expressed sap, but remains behind in 
the residue, either because it is insoluble or, perhaps, is still part of 
the protoplasmic complex. Experimenting with the whole organ 
after freezing gets over this difficulty, and one is enabled to 
determine the C0 2 output of the same organs before and after this 
killing. 
Palladin makes the interesting observation that the heightened 
respiration during life, produced by ether or quinine, has no 
persistent effect in the way of increased C0 2 -output from the 
enzymes of the part after freezing. From this he concludes that 
the C0 2 of respiration has at least a double origin, part coming 
from enzyme activity, and a part, which he calls “Reiz-C0 2 ” 
(stimulus-C0 2 ), coming from the protoplasm itself as a result of the 
stimulus of the ether or quinine ; the latter part disappears on killing 
the protoplasm. So also the immediate increased output of C0 2 
on wounding bulbs has no counterpart in the C0 2 -output after 
freezing, being “Reiz-C0 2 ,” while the reparative processes that set 
in several days after wounding lead to an increase of tissue proto¬ 
plasm and of enzymes, and so produce an increase in the C0 2 - 
output, as compared with an uninjured control; and this persists 
after killing. 
1 Ber. dcut. bot. Gcs. XXIII., July, 1905. 
