[Vou 2 
824 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
one of the forms falling within the scope of this study, experi- 
ments were carried on to determine the presence or absence 
of nucleases in one representative of each group, Ulva, Ce- 
ramium, and Ascophyllum. 
One-half per cent nuclein was dissolved in N/10 NaOH, 
the complete solution of the compound being shown by a 
drop of phenylphthalein. One hundred ce. of this neutral 
solution were added to each flask together with 3 grams of 
air-dried algal powder. Toluene was added as an antiseptic. 
Checks were set up by adding autoclaved algal powder to the 
nuclein and also by using nuclein solution alone. The flasks 
were placed at 35-36°C. for 38 days, at the end of which time 
the phosphoric acid split off was determined as P2Os by the 
uranium-acetate method. Five ec. of a sodium acetate solu- 
tion? were added to 25 ec. of the nuclein substrate, this brought 
to a boil and titrated while hot. Potassium ferrocyanide was 
used as an indicator—a drop of the titration mixture being 
removed from time to time and brought into contact with a 
drop of the indicator on a porcelain plate. The results ob- 
tained are given in table xvii. 
TABLE XVIII 
THE ACTION OF POWDERED TISSUE FROM CERTAIN ALGAE UPON NUCLEIN 
Substrate Free HsPOs as P2O5| Net amount 
100 cc. Weight algal powder in 100 cc. in 38 days} POs in 100 cc. 
1 per cent mgms. mgms. 
3 gms. Ceramium 70.00 56.25 
3 gms. Coromsuim boiled Ute = «Il “ Goaes 
: 3 gms. Ulva 56.70 39.20 
Nuclein 3 gms. Ulva boiled 1750.8 9 ben ees 
3 gms. Ascophyllum d/25 Se) 
3 gms. Ascophyllum bld. 16:90" - 5. oR eels 
These findings substantiate those of Teodoresco (712) re- 
garding the general presence of nucleases in the algae. The 
values for Ceramium agree very well with those he obtained 
for the same form, 1. e., 56.25 milligrams in 38 days at 35°C., as 
compared with 76.6 milligrams in 51 days at 22-26°C. Ulva 
1 The standard solution of the uranium acetate contained 8.8652 grams of the 
salt in 250 ce. of water, and each cc. by calculation was equivalent to 5 milligrams 
of P2Os5. 
*The sodium acetate solution contained 25 grams of sodium acetate and 25 
ec. of 30 per cent acetic acid in 250 ce. 
