134 
THE REFRODUCTION OF ASCOMYCETES. 
the Mucorines, and which he has figured in the “ Annales des 
Sciences Natiirelles,” 5th serie, t. xvii., pi. 20, f. 1. 
The spores were disposed in a drop of liquid and placed upon 
the thin glass cover. This last was supported by its edges upon 
those of the cell, the drop occupying the inferior face. One can 
then, by the aid of the microscope, explore all the points of the 
drop of water, the inferior surface of which is in contact with the 
air. In order to prevent dessication, a big drop of water was 
placed at the bottom of the cell. In order to fix the cover, one 
must not use anything oily, which would obstruct the renewal of 
the air, but, by two small pellets of soft wax, fixed with a flat 
needle upon the edge of the cell, the air can circulate, and be 
gradually renewed. The whole was placed in a damp chamber 
formed of a square tin case, containing a brick dipped in water ; 
the case was covered by a sheet of glass at a little distance from 
the surface of the brick. 
In this narrow space one can preserve moist, without adding 
w^ater, preparations thus disposed for more than six months ; they 
do not dessicate, even thus long. The spores disposed upon the 
covers were in contact with the air, renewed in an atmosphere 
which stopped the dessication of the drop of water. 
In order to avoid the introduction of strange spores by the 
nutritive liquid, and, above all, the development of bacteria, one 
spots, by making of all fragments, as M. Eaulin did in his cultures 
of Aspergillus niger^ a liquid, by the aid of chemical substances 
pure and exempt from germs. The liquid, containing yL of 
sugar, and of tannin dissolved in distilled \vater. These two 
substances are encountered simultaneously in the bark of the wood 
of the greater part of the phanerogamous plants upon which 
develop so great an abundance of Ascomycetes. The addition of 
an acetate matter in the nutritive liquid (yJ-Q of acetate of am- 
monia and of sugar) was tried, but this second liquid did not 
appear to give such good results as the first. 
The difierent species experimented upon have been chosen at 
hazard, according as the chances and facilities occurred of easily 
procuring those which presented spermatia sufficiently clear and 
easy to determine. 
One of the species on which one finds it commonly is the 
Diplodia acerina. The long branches cut during the winter of 
1870 and 1871, and preserved in faggots without too much damp, 
were covered with spermogonia in the following spring, and 
furnished good materials for study ; the dead branches of Cratcegus 
oxyacantha, made into brushes, frequently present the Diplodia 
vulgaris and its spermogonia, which are scarcely ever wanting. 
These two Diplodia have given me excellent results. 
The spermatia which accompany the Diplodia acerina are very 
narrow and curved in an arc ; sown upon a nourishing liquid their 
form modifies at first, without augmentation of length ; they 
