Mould Growths upon Cold-store Meat. :129 
(b) Temperature relations. The forms were grown at different 
temperatures. Very slight indications of growth on artificial 
media at — 6° C. have been obtained in some strains after long 
periods, and as the majority of forms develop well at 2° C., it is 
likely that better growth occurs just below o° C. than at — 6° C. 
The large white spots sometimes seen on meat have probably 
arisen through exposure to temperatures round about freezing 
point; there is no indication yet that such large growths would 
develop at — 6°C.° 
IV. CULTURAL DIFFERENCES OF STRAINS OF S. CARNIS. 
Scarcely any two isolations appeared identical in culture, but 
they can be arranged conveniently in four groups, according to 
their macroscopic appearance on Sabouraud’s glucose agar, the 
medium on which they grow best. The microscopical characters 
of the strains are so similar as to be of no value for differ- 
entiating them. 
1. F Group: comprising forms F, 121A, 1048, all isolated from 
meat in cold storage, and L, isolated from a Petri dish 
exposed in an abattoir in the Argentine. 
This group is distinguished by its rather smooth colonies, 
which are not heaped up on the surface of the medium as in 
the next group, and by the development of a yellow pigment 
on almost all media used. 
2. W Group: comprising forms W, 102E, 120B, I10A, all 
isolated from meat in cold storage. 
These are very closely related and are characterised by their 
colonies being usually heaped up on the surface of the medium. 
In colour they vary from white to brown, and they produce 
no yellow pigment in the medium, as in the preceding group. 
Instead, in some liquid cultures they produce a dark brown 
pigment, diffusing through the liquid. 
3. “Woolly” Group: comprising I18D, 120C, 103A, IOTA, I04A, 
all isolated from meat in cold storage. 
The extreme ‘“‘woolliness”’ of these strains on all media dis- 
tinguishes them from the other groups. The colonies are dirty 
brown in colour. These strains produce no yellow pigment in 
the medium, but some produce the dark brown pigment noted 
under the preceding group. 
4. 119C Group: comprising I1g9C and 115G, isolated from meat. 
On all media used these strains have very dense, smooth 
colonies, quite different from other groups. The colonies show 
M.S. 9 
