196 : BOTANICAL GAZETTE © [MARCH 
solution, about 0.02 per cent of sodium hydroxide was added to the 
water with which the colloidal solution was prepared, so that this 
solution contained NaOH. Two experiments were carried out with 
TABLE I 
CULTURES OF SPIROGYRA LONGATA IN COLLOIDAL SILVER SOLUTION, WITH AND 
WITHOUT ADDITIONS 
Silver in medium, | Other substancesin| Condition of Duration of 
Culture no. ae apa oe plants* experiment, days* 
Te Ce OOO ae ee DD I,1 
Ticks 0 D 1 
cS. GS ee D I 
16 eee Bees ae ees ee D I 
| een ea ee Oe or eee a ac D I 
» | SERS Te aA ia coo Aaiageus urinates, SEN ere gem D I 
sf yen es eaten ee Sie ONG. he Po ey Pb 1,1 
SAG Ra gt Se TE, SOO selee Bageaes nt E t 
st Soe hay cere D009 ee Gp 3 
iF Pied ete eg I OORR— a oe E . 
10 pay ae pee O- OOS hi ten ei G, D 3,1 
ey Se arate eee re 0.045 Salts to form E, Eg 2,1 
0.5 p.c. 
Crone’s solu- 
tion 
Me 0.0135 : E t 
Bik See 0.009 do. Eg 3 
Me ©.0045 do. E 
cele Cette enon 0.045 Colloid. Pt, 81 E,E 2,1 
ppm. 
eee aaa tra 0.0135 do. E 
CeO oe ©.009 do. E 3 
See ee 0.0045 do. E : 
4B ie 0.045 Animal char- 
coal, o.1 gr. E, G 2,1 
Pe Se ors 0.0135 do. E . 
Mio ee 0.009 do. E 3 
Ads ae 0.0045 do. E : 
[ee 
*In tables I-IV th Ate: +h oe a ee ee E, excellent, meaning that none of 
fil nts i * i; G, good, : ee - LW 3 2. j a D ig poor, . 
more than half i injured; D, dead, meaning that all or practically all the filaments were dead. 
: Where the experiment was repeated, estes 
e several notations g fers to a single exp t. The numbers in the last column (duration 
i ° £ } denoting duration 
Pee a 4 i } 
; thus, 
. 
combination of letters denotes a condition between those denoted by the combined letters, 
S Eg Aiti. het oll, a good. fuk 
etc. 
cod 
Spirogyra from the stock culture, filaments being transferred to the 
undiluted, alkaline solution of colloidal gold (II, 5a). In one case 
the filaments remained in excellent condition during the period of 
the experiment (2 days); in the other case, the alga remained with- 
