1911. ] On Variation and Adaptation in Bacteria. 547 
Table III.—Streptococci L, P,8,G,M, Hand V. Showing the Changes of 
Reactions (20 out of a possible 49) which had taken place after the lapse 
of Two Years. 
aw | | >) 
: 5 Biel Me 
S Date of 6 S) © 3 aq SI 2 
fi oH nl o 5) ocd ra) 
$ testin S eS D ° 5 d = BS AS) q 
a 2 ea Stal qo) cee Pe ee liceaue Ona ie me 
a TH © ) 3 S =| 8 >a) 
a mel BJS alos aid aS ese) eesti | Fe pa te 
| 
L | June, 1908 . + ea 0 0 0 0 
Peloton... 0 0 eek 0 Ona lpe ce 0 2 2 4 
P a LOOBY ac + 0 + + 0 + 0 
at LOLO™, O 0 + OF 0 + 0 0 Py SN 
Ss in! OOS san 2: dt sb + | O e + 
seh LOLOR al -O + + Ont ier 0 + O 0 3 3 
G PRT OOS oN. Nie 8 4s + (0) Se seri Fria 
et  OLON i: SE + + up | al + O.. ad 2 3 
M i eLOOS 85.10. e + + + 8) “Pati O 
Pee TOON. O 4 “ 0 0 eau a0 0 2 2 
H me H1G08)1 21.4 0 ma rs fe stay Nid es 
ey LOOT FS. oO + + O Oe Way ead Min 0 2 2 
avi Pe OOS sal te + | 0 O + + 0 
MOTO TON 2.70 0 ee eee a eae 4 0 0 + 0 1 3 4 
Seven streptococci selected as giving each a different series of reactions 
when first tested in 1908. Land P had been under cultivation in the 
laboratory for more than a year, while 8, G, M, H, and V had recently been 
introduced from Copenhagen. 
These results show that, when examined after longer or shorter intervals of 
time, the reactions of the streptococci tested exhibited marked changes under 
the conditions of ordinary cultivation. 
The seven strains of streptococci shown in Table III were now chosen for 
further investigation. 
P, which had never fermented saccharose, was grown in the saccharose 
medium. 
L and V, which had never fermented raffinose, were grown in the raffinose 
medium. 
M, V, and H, which had never fermented mannite, were grown in the 
mannite medium. 
The cultures were sub-cultivated every three days in the appropriate 
medium. The course of the experiments was as follows :— 
