228 Barker.—A Fragrant ‘ My coderma ’ Yeast , 
gelatine, but usually only to a slight extent. The amount 
of liquefaction that takes place varies considerably. During 
the autumn of 1899 apparently contradictory results were 
obtained from observations of the behaviour of plate-cultures 
of beer-wort gelatine and streak-cultures. 
On some plates the gelatine was completely liquefied, while 
on other plates it remained quite solid : similarly also with 
streak-cultures. In some cases the gelatine in the neighbour¬ 
hood of one or two colonies would be liquefied, while on the 
rest of the plate the gelatine remained solid. Thinking that 
these results might point to the presence of bacterial infection 
or of more than one variety of Yeast, the matter was tested 
by repeating the plate cultures, with the same results. Fur¬ 
thermore, hanging drop cultures from a single colony on a 
plate on which the gelatine had remained unliquefied were 
made, using beer-wort gelatine as the medium, the gelatine 
being in the proportion of ten per cent. The drops were 
kept under observation under the microscope, and the state 
of the gelatine in the neighbourhood of the Yeast-cells 
observed. It remained unliquefied until a colony of cells was 
produced, and then, in every case observed, it was eventually 
found to be slowly liquefied in the immediate neighbourhood 
of the cells, but the liquefaction did not in every case extend 
to the rest of the gelatine. Also the size of the colony, 
when the first appearances of liquefaction were observed, 
varied considerably. In drops four days old sometimes a 
colony was produced as large as a pin’s head, quite dry and 
glistening white in appearance, and standing out above the 
surface of the gelatine. In such cases the gelatine was 
liquefied only in the immediate neighbourhood of the cells 
imbedded in the gelatine. In other cases the whole drop 
would be' liquefied, and the Yeast would form a greyish-white 
film over the surface. These facts negative the idea of 
bacterial infection, since no Bacteria could be observed in 
the drops, and also the idea of a mixture of Yeasts of different 
properties, since cases in which drops were made from the 
same colony show the different results. 
