THE STREPTOTHRICOSES 587 
Litmus milk. — No change for six days, then beginning slight alka- 
linity which increases very little, shows digestion of the caseinogen, 
slight, thin filmy growth on surface. 
On media such as litmus lactose agar and old Endo it grows slowly 
on surface and assumes the color of the medium. 
Broth. — Only surface growth appearing during early generations, 
after 3-6 days as a wrinkled, pale yellow scum very much like the 
tubercle bacillus growth; later generations grow perceptibly in one to 
three days. Medium perfectly clear. If a large mass be seeded into 
neutral broth there is a perceptible increase in the growth after ten 
days. The medium thereafter tends to a faint turbidity. Titration 
of broth growth after twelve days shows alkalinity requiring 0.3 cc. 
decinormal acid, while the control tube incubated same length of time 
showed an acidity requiring 0.57 cc. of decinormal NaOH. 
On the following sugars there is a slight surface growth without 
change in the color, Andrade indicator — dextrose, lactose, saccharose, 
maltose, mannite, dextrin, galactose, salicin. 
Cultures observed on two per cent, neutral agar. 
A. — Stained by Loeffler's stain. 
Twenty-four hours. — Shows threads growing out from a central 
amorphous mass, but the whole does not retain the regularity or 
parallelism of actinomyces. Threads are poorly stained and rather 
disconnected but not jointed. Small number of metachromatic bodies 
apparently in older individuals, certainly in the better formed ones. 
No intercalary spores, unless the metachromatic bodies be so con- 
sidered. Individual threads measure from one-third to one micron in 
width. Metachi'omatic bodies measure on the average one micron. 
The threads in the forty-eight hour preparation seem distinctly 
wider, up to one micron and possibly become heavier toward the end, 
but do not have a distinct bulbous extremity. 
In three days the threads are much longer, show distinct branch- 
ing and a tendency to transverse segmentation. More than one meta- 
chromatic body may be present in one segment. 
Four days. — Still coarser, short segments have appeared separately. 
Metachromatic body is coarser and blacker; some of the masses have 
gone to pieces and show only a diffusely staining smudge of metachro- 
matic bodies. The short segments show a tendency to grow out 
into threads. 
Fifth day. — Condition is much the same plus many young, delicate, 
poorly staining threads. 
Sixth day. — The same but all seem to be somewhat wider and 
diffusely staining. 
Seventh day. — More diffuse staining and decidedly fewer meta- 
chromatic bodies. 
A. — Stained by Gram's stain. 
Twenty-four hours. — All forms are light purplish. The threads 
stain much more clearly than by Loeffler's and show distinct transverse 
