hi 
bacterium occurs invariably in malignant granuloma. In our opinion 
this seems to be the case, as may be concluded from the literature 
that appeared hitherto. Still, even if this be so, it would perhaps 
not by itself entitle us to consider that corynebacterium, beyond a 
shade of doubt, as the etiologic moment. 
We purpose before long to write more at length about this subject 
in another publication. 
EXPLANATION OF THE PLATE. 
Fig. I Smear from the spleen v. d. S. Gram-stain with counterstain. 
„ i 48 hours’ Bordet-culture, cultivated directly from the spleen of v.d. S. 
Gram-stain with counterstain. 
„ Jil 18 hours’ Bordet-culture after one transplantation. Gram-stain without 
counterstain. 
» IV Rod with branches from fluid Bordet-medium. Gram-stain with counterstain. 
» V 5X24 hours’ ascites-agar-culture, grown directly from the spleen of 
v. d. S. Gram-stain with counterstain. 
„ VI LOrFFLER'S serum-culture transplanted after 12 weeks from original 
LogFFLER’s serum-culture, obtained from a gland of patient S. 
Physics. — ‘Measurements on the ultraviolet magnetic rotation in 
gases.” By Dr. J. F. Smxs. (Communicated by Prof. KAMmrr- 
LINGH ONNES.) 
(Communicated in the meeting of October 26, 1912). 
1. To get an idea of the relative values of the various theories which 
have been developed to explain magnetic rotation, measurements may 
be made in the neighbourhood of absorptionbands and -lines in the 
visible spectrum with a view to ascertain whether the rotation has 
the same’) or opposite sign’) on either side of the absorptionband. With 
perfectly transparent substances one could extend one’s observations 
over a much wider region of the spectrum so as to ascertain if the 
experimental results obtained in the ultraviolet, for which the rotatory 
constants “are much greater, can be more satisfactorily represented 
by the one theory than by the other, and if, perhaps, a strong increase 
in the rotation takes place on approaching the ultraviolet region. 
With gases, and in particular with hydrogen, where, on account 
of their simple molecular structure ordinary refraction of light can 
well be represented by the assumption of a single kind of ultraviolet 
electrons *), and for which the value of ¢/, may be obtained from the 
1) Vorer, Magneto- und Elektro-optik p. 133. 
Drupe, Hypothese des Hall-effektes, Lehrbuch der Optik p. 429, 1906. 
*) Drupe, Hypothese der Molekularströme, Lehrbuch der Optik p. 419. 
8) ABRAHAM, Theorie der Elektrizität Il, p. 261, 1908. 
50* 
