67
THE ARTIFICIAL PROPAGATION OF MABINE FISH
500
experiment indicated the presence of ponicillin-streptomycin reeietent
bacterh giving small yollow colonies with the distinotive smell of
musty hay. Although the U.V. system (unit 1) gave a 100% kill of
btloteria in the sea-water inflow, oontaminants were i n t d u o e d with
-
Hotching
Estoblishcd
Metomorphosis
complete
feeding
complete
stock
0 1
I
I
I
I
I
1
1
I
I
1
0
1 0
20
30 4 0
5 0
6 0
70
80 90 100
D a y s a f t e r s t a r t of experiment
h. 16. Provisiond stlrvivel curvea from an experiment to dstarmine the mlstive
merite of anti-biotic v d ultra-violet treatment in phah-redng.
k ~ d
food, and these proliferated in the m h g tanks to produce
beoterial populations no less dense than in the controls.
The visible influence of anti-biotio treatment was most clearly seen
at the time of hatohing. The caet-off egg shells from unita 1 and 2
Were only slightly opaque; those from the untreated controls were
notioeably cloudy, though not to the same d e p as Been in former