396 BOTANICAL GAZETTE [DECEMBER 
thought desirable to test this salt on account of its wide use as a 
preservative in laboratories and elsewhere. It proved somewhat 
more toxic than HCl, but not so fatal as HNO,. Cdocephalum 
was quite susceptible to its influence, —s being fatal. It is not, 
however, of much value as a disinfectant, over I per cent. being 
necessary to prevent the development of molds. 
In the following table the various agents are arranged in the 
order of their toxic properties as shown by their powers of inhib- 
iting germination of the spores of the five species of molds used. 
The fifth column gives in round numbers the number of mole- 
cules of each substance required to produce an inhibiting effect 
equal to that of one molecule of mercuric chlorid. The coefficients 
us n 
have the usual value of x in the expression, ——; of -. 
2048 I 
TABLE IL 
Agent Formula psig eae of Ratio 
injury | inhibition |death-point 
~Mercuric chlorid  - . HgCl, .026 281 -331 te 
Potassiu Cette K,Cr,O, .094 1.25 va 
Silver nitrate - AgNO, 013 375 275 1.3 
Potassium hindiate : K,CrO, 156 4 2.25 1.4 
Formaldehyde - HCHO S531. hae be 5: 
ydrocyanic acid HCN 965. 3, 20. oa 
Cadmium nitrate - Cd(NOg)s 075| 6.1 24. se 
Potass yanid KCN 2.2 25.6 | 77: oe 
Nickelous sulfate -  - NiSO, 4.8 | 733-6 ss 8 
monium hydroxid NH,OH 8 51. 83 A 
Cobaltous sulfate - CoSO, 6 57.6 389. ae 
Monochloracetic acid - CH,CICO,H 8.8 58. 64- lle 
ia ic acid - - CHCI,CO,H 10.4 64 64. ob. 
Ac cid “ CH,CO,H 25.6 a3. 314- ce 
Pi chloracetié acd - “ CC1,CO,H Ree go. 115 Eur 
Hydrogen peroxid— - ,0, 38. 105. 127. a 
Ferrous sulfate - FeSO, 14.4 IIS. 2150. i. 
Copper sulfate - - CuSO, 131 82. 4 9 
Sopper nitrate a Cu(NO,)» 8.4 134. 634 sas 
N d ee HNO 48. r4t. 384 
Potassium hydroxid KOH { 19- | 166. | 282+ 593- 
Sodium salicylate a Oo: Reape Na 24. 182 182+ oe 
_Sulfuric acid - —- - %H,SO, . 61.. | 205. 589% oe 
H eauaehione acid - HCl 70. Sa pis: 2150: 
Zin ulfate - . ZnSO, 26.4 | 602 3072. 
Strychnin sulfate : C,2Hgg.N,0,H,SO,4| 179 8775+ 
Potassium iodid : K 384. |2457- [495° | oy, 
Ethyl alcohol — - - C,H, OH 717. |3686. peniebte  ° 
