( 677 ) 
that nearly */,, is assimilated for the building of the bacterial 
bodies. 
Splitting and assimilation of fat at the denitrification were deter- 
mined as follows. 
In an ERTENMEYER flask of 300 cc. capacity a certain quantity of 
fat was weighed and the flask closed with a rubber stopper, fitted 
with a bent glass tube for gas outflow. After the apparatus had 
been sterilised and heated the fat was spread over the inner surface 
by rotation. After cooling 300 ce. of the following nutrient liquid 
was introduced: 100 tapwater, 1 kaliumnitrate, 0,05 bikaliumphos- 
phate; inoculation took place with one of the denitrifying bacteria. 
The cultivation took place at 28° the evolving gases- were caught 
over paraffin oil or caustic alkali. 
Before the evolving of gas begins the oxygen above the culture 
is assimilated, the fat first undergoing hydrolytic splitting. 
From June 28, 1909 to July 8 B. denitrojluor. non lq. formed 
57 ce. nitrogen and 1.5 ec. carbonic acid with 0.4385 gr. of fat. The 
rapidity of the process had then decreased so much that it was 
resolved cautiously to renew the culture liquid without loss of fat. 
The decanted liquid reacted feebly alkaline, and contained nitrate, 
nitrite and glycerin, whilst per 25 ee. liquid 5.1 ee. carbonic acid 
was present. After the refreshing the fermentation velocity increased 
again, thereupon it decreased slowly. The total production until 
August 18 with the 0.4385 er. of fat that had nearly disappeared, 
was 230 cc. nitrogen and 142.6 carbonic acid. If we neglect the very 
slight quantity of the still present saponaceous substances, about */, of 
the carbon of the fat is transformed by the denitrification into carbonic 
acid and +*/, into bacterial matter and insoluble organic compounds. 
In the culture liquid no intermediate products could be pointed out ; 
evidently, also in this process the oxydation of the fatty acid only 
produces carbonic acid and water. 
In Pl. 4 fig. 4 the rate of rapidity of the process is graphically 
represented. The evolved gas volumina per 6 hour’s, cultivation are 
noted on the abseis; one centimeter representing a em.* of gas. On the 
ordinate the time is noted, one day being represented by one cm. 
We can very well perceive the increase in rapidity of the gas 
production after the refreshing of the culture liquid on July 8; yet 
the angle of inclination of the line is much smaller than that at the 
beginning of the process. 
The cause of this falling must not be attributed to the formation 
of soluble secretion products of the culture, as is often the case in 
bacterial cultures, but to the presence of a thick layer of bacterial 
+4 
Proceedings Royal Acad. Amsterdam, Vol. XIIL 
