d4 
liver is really a tissue for which the above does not hold or whether 
the fixation had been insufficient I have been unable to settle. 
Summarising we may state that for the mesentery, the outer 
stratified epithelium of the cornea and the epithelial cells of 
LIEBERKUHN’s crypts of newborn cats a period in the mitotic nuclear 
division is observed with a maximum in the evening, the night or 
the early morning hours, a minimum in the later morning hours 
and the early afternoon. The maximum number of karyokineses 
does not always occur at the same time, but never in daytime, the 
minimum is always at the middle of the day. 
Further investigation will perhaps reveal that also other tissues, 
as well of the cat as of other animals, show the same phenomenon 
and this may be the reason why in general in growing tissues no or 
very few karyokineses have been observed, since the fixation of the 
tissues has commonly taken place at the middle of the day. 
Anatomical Cabinet 
Leyden, February 1916. Histological Department. 
Physiology. — “The electrical phenomenon in cloudlike condensed 
odorous water vapours’ examined by Prof. Dr. H. ZwaAARDE- 
MAKER in collaboration with Messrs. H. R. Knoops and M. W. 
VAN DER BULL. 
(Communicated in the meeting of March 25, 1916). 
That odorous substances are often present in the air in the form 
of water vapours with a cloudlike condensation and in that state 
stimulate our sense-organ was first suspected by J. Gautn') in the 
year 1900. A frequent occurrence of this phenomenon seems to me 
to be improbable *), still, I felt called upon to look more closely at 
the sensory qualities of odorous water vapours with a cloudlike 
condensation, when a suitable apparatus to produce them should be 
at my disposition. 
Such an apparatus was devised two years ago by Prof. G. GRADENIGO, 
who made use of a simple glass sprayer, of the adiabatic expansion 
of compressed air, supplied under an over-pressure of two atmos- 
pheres and of the splashing of the waterdrops against a glass wall *). 
1) J. Gacre in P. Heymann’s Hdb. der Laryncologie und Rhinologie. Bd. III 
p. 178 Wien 1900. 
*) Gf. my “Physiologie des Geruchs’”, p. 22. Leipzig 1895. 
35) The apparatus still used by us is the one Prof. GRADENIGO kindly made 
me a present of. A description of it will be found in Arch. int. de laryngologie, 
d’otologie et de rhinologie. 1911. 
