Ward. — Symbiosis. 
557 
as measured by the amount of carbon-dioxide evolved. Effront, 
in 1894 (42), showed that hydrofluoric acid acts similarly on 
yeasts, butyric ferments, and Mycoderma , and, later, that the 
same is true of formaldehyde, salicylic acid, picric acid, & c. 
The results of Johannsen\s experiments with seeds, buds, 
&c., treated with ether or chloroform, look like another case 
in point : respiration is increased, and the whole course of 
metabolism so altered that in some cases buds of flowers can 
be stimulated to open long before their normal period (48). 
The results obtained by Farmer and Waller with carbon- 
dioxide, which was found to induce an initial acceleration of 
the movement of the protoplasm in Elodea , may be a further 
instance (44). 
Pfefifer has recently called attention to a still more remark- 
able instance — that it is possible by etherizing the living cells 
of Spirogyra to alter the type of nuclear division from mitotic 
(indirect) to a-mito tic (direct). Massart had shown that callus, 
the hypertrophied tissue developed under stimulation by mites, 
fungi, exposure to air, &c., is formed of cells which divide 
with a-mitotic nuclear division ; and other cases occur. But it 
is even more to the point for my purpose that Gerassimofif, in 
Pfeffer’s laboratory, found Spirogyra driven to a-mitotic 
division by associated Bacteria and other organisms, which he 
regards as a case of symbiosis (44 a). 
Now it may be regarded as certain that if a cell can be 
thus stimulated to alter the details of so fundamental and 
complex a morphological process as its cell-division, by the 
action of associated organisms, the metabolic activities of 
its protoplasm are being driven into very different channels 
from the normal, and many physiological processes must 
be affected. 
Of course I am here raising questions which concern the 
border-line between health and disease, and much investigation 
is still required as to the meaning of these matters ; but I ought 
to add that according to Pfeffer the etherized cells can be again 
restored to their normal state if the traces of the anaesthetic 
are washed out, and those familiar with Klebs’ experiments on 
