746 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
fluid in the bottle B runs up the tube c, and thus the air is prevented 
from escaping backwards. The bottle A is meanwhile filled with air 
through the tube b. 
When the bottle A is almost empty the water in the siphon d falls, 
provided the lower end in- 
F IG> 9 i side the flask be sufficiently 
broad, and the water flowing 
back without interruption 
again drives on the air into 
the cultivation vessel. There 
is no other outlet for the air 
as the siphon d and the tube b 
are closed by water. The 
amount of pressure with which 
the air is forced out depends 
on the height of the tubes 
b,c,d : the longer they are the 
greater the pressure. 
If the water runs into the 
bottle A too quickly, the air 
pressure rises too high in the 
bottle, the water is forced into 
the siphon d, so that the bottle 
A is emptied too soon and 
before it has become properly 
filled, but if the water inflow 
be regulated the apparatus will 
be found to work with great 
regularity. 
Cultivation Capsule for 
Fungi.* — Dr. J. H. Wakker 
describes an apparatus which 
he has devised for cultivating 
fungi in the tropics, where it 
is necessary to use agar as the 
nutrient medium. It is a 
simple glass capsule in the 
middle of the top of which is 
an opening o, with the funnel- 
shaped piece h above (fig. 92). 
The free edge of the funnel 
has a thick lip r. The top 
a a forms a movable lid for 
the capsule, which can be se- 
curely closed. The funnel is 
stopped with cotton-wool w , and protected against dust by a rubber 
cap /. When a layer of the medium has been poured in the capsule is 
Centralbl. f. Bakteriol. n. Parasitenk., xvi. (1894) pp. 348-9 (2 figs.). 
