352 
which resembled torula cells, and occasionally penicillium 
acrospores. 
From this result we do not, however, conclude that it is 
by these forms that the cosmopolitan fungus (as Hallier calls 
it) is usually propagated ; it frequently happens that liquids 
which have been once exposed, although they contain no 
visible cells whatever, rapidly germinate without further ex- 
posure. We are also certain that although air is the main 
source of what we may venture to call fungus impregnation, 
as distinguished from impregnation with microzymes, yet the 
two acts may take place at the same moment—germs of 
torula being often contained in the same liquid media as the 
germ particles of microzymes. ‘That this is so is proved by 
instances already referred to, in which liquids protected from 
air filled with torula cells. Here we relinquish this question, 
although in a biological point of view it is of the greatest 
interest and importance. 
On the CoLour1nc Matter of some APHIDES. 
By H. C. Sorsy, F.R,S,, &e, 
TuosE who have orchards are no doubt often only too 
familiar with the red Aphides found in downy patches on the 
bark of the apple tree. These are coloured by a substance 
possessing somewhat remarkable properties, connecting it on 
the one hand with cochineal, and on the other with the 
hemoglobin of the blood of vertebrate animals. It rapidly 
changes into a series of new products, which have remarkable 
optical characters, and are in some respects analogous to the 
colouring matters of oils and fats. 
In order to obtain this red colouring matter in a state 
suitable for examination, the insects, fresh taken from the tree, 
should be crushed up in a small quantity of boiling water, 
and the solution filtered. It is then of a fine crimson colour, 
giving a spectrum with a broad general absorption, extending 
from the yellow over the whole of the green to the centre of 
the blue, without any well-marked narrow band, as shown in 
No. 1 of the accompanying fig. 1.. 
