Life in Solutions of Colloidal Silica. 387 
found that they stained uniformly with various dyes, but showed none 
of the contents which are so characteristic of living fungal hyphae. It 
is clear that the threads in question are merely deposits of colloidal 
material simulating only in a slight degree the hyphae of a fungus. 
The author has never obtained in sterilized tubes any growths of 
a typical fungal or Torula-like nature, and no growth has ever developed 
in nutrient media which have been inoculated from the tubes at the time 
of opening. In cases, however, where the tubes were not sterilized at 
all, or where they were allowed to stand for a week before being sterilized, 
there have usually been found rudimentary mycelia of a very crumpled 
appearance. These were obviously dead, and surrounded by a deposited 
layer of silica. In most of these cases it is fairly easy to trace the spore 
from which the mycelium has developed, although this is not always 
possible. Fig. 8 represents one of these growths from a tube which was 
prepared, sealed, and left eight days before being sterilized by intermittent 
sterilization at ioo° C. Here the spore is quite obvious, and there can be no 
doubt that similar growths must inevitably be introduced with the solutions 
if these should have been made even a few hours before being filled into the 
tubes. 
The growth shown in PI. IX, Fig. 9, was observed in a tube containing 
colloidal silica and ammonium phosphate which had been opened and left 
standing for five months. The microscopic appearance is strikingly similar 
to that represented in many of Dr. Bastian’s figures. At the time of 
observation this fungus was dead and the cells, when treated with Delafield’s 
haematoxylin, exhibited contents or some remains of organic material such 
as are typical of the disorganized contents of a fungal mycelium. 
A very similar growth was also obtained in a solution of colloidal 
silica during the process of dialysing in a parchment dialyser which had not 
been sterilized. 
That growths obtained under these conditions so closely resemble 
those found by Dr. Bastian would seem to suggest that the conditions 
under which circumstances forced him to labour were not always conducive 
to perfect sterility of his solutions. 
All these observations support the view which has frequently been 
urged by others that the organisms described by Dr. Bastian were either 
purely inorganic silico-morphs, or else were produced by the deposit of 
silica on the surface of dead fungal hyphae or yeast cells which had de- 
veloped in the solutions before these were filled into the tubes and sterilized. 
This work was completed and ready for publication at the time of 
Dr. Bastian’s death, and it is a matter for regret that he is no longer 
with us to take up the challenge. His work has aroused considerable 
interest in certain quarters, and it therefore seems advisable to place 
these observations on record. 
