( 381 j 
organisms abiding near the bottom, Diatomaceae, of the benthos. 
These bottom-Diatomaceae however are found not to be equally 
abundant in all parts of the Eastern-Schelde-bed, but their appearance 
is very markedly connected with the nature of the sea-bottom. The 
latest investigations of G. KARSTEN, who has made the bottom- 
Diatomaceae in the Gulf of Kiel a subject of his studies, have now 
made it very probable that different nutritive salts which are present 
in the bottom of the sea, have an active part in the development of 
those Diatomaceae; a part comparable to that which they play in 
the development of agriculture. Whether certain bacteria will prove 
to render the same important services here as in the growth of our 
agricultural plants, can as yet only be supposed, however probable 
this may be. It is already obvious however that exhaustion of the 
soil, in consequence of overpopulation in the oyster-culture, is 
equally imaginable as in any other culture. 
The speaker hopes soon to be able to present to the Academy a 
copy of the report on his investigations, for which he has obtained 
considerable co-operation from different sides. 
Physiology. — “A new law concerning the relation of stimulus 
and effect.” By Dr. J. K. A. WERTHEIM SALOMONSON. (274 
Communication). (Communicated by Dr. C. WINKLER). 
In a former essay I have formulated a law expressing the relation 
between the magnitude of a stimulus and the effect operated by it. 
Our deductions were based exclusively on wellknown physical prin- 
ciples, viz. on the fact that an infinitely small increment of stimulus 
will cause an infinitely small but proportional increment of con- 
sumption of the substance by the transformation of which the effect 
is occasioned, whilst we admitted finally with GULDBERG and WAAGE 
that the magnitude of this transformation, must be proportionate to 
the quantity of transformable substance. Starting from these perfectly 
admissible premises, we finally found a law, expressing the relation 
we were in search of, in the following formula: 
Li À ; 1— ¢«—B(k-0)} 
We tested this law in the first place to the reiation of stimulus 
and muscle-effect, and arrived at the conclusion that on this point 
there existed a perfect accordance between my law and the results, 
obtained experimentally by other investigators. 
In this way we proved the validity of the law for the muscles. 
We will try now to examine whether our law prevails also in 
regard to other organisms or parts of organs, 
