1041 
The experiments on which these conclusions are based are as follows: 
(1) The resistance in ohms (R) was measured in a certain conductivity cell, 
the following solutions being used: 
(a) 25 ce. 1 per cent sodium chloride solution, Re=— 72.4 
(b) 25 ce. of 0.5 per cent saponin solution+0.08 per 
cent sodium chloride, Re—'.63.9 
(c) 25 ce. of (a)+25 ce. distilled water, R==138.1 
(d) 25 ee. of (b) +25 ce. distilled water, Re 20.2, 
(e€) 25 ce. of (a) +25 ce. of (db), R= 66.45 
(e€) 25 cc. of (2) +25 ce. of (b), R=—.65.9 
(e) 25 ce. of (a2) +25 ce. of (b), R=—. 65.9 
(e) 25 ce. of (a) +25 ce. of (b), Rie=='66.65 
(e) 25 ce. of (a) +25 ce. of (db), R= 67.0 
(€) 25 ec. of (a) +25 ce. of (b), R= 66.5 
Calculated [from (c) and (d)] resistance, if one 
solution has no effect on the ionization of the other, 
for (e) in ohms, 65.4 
Hence a very slight reduction in conductivity is observed on adding saponin. 
Another series gave similar results as follows: 
(a) 0.1 per cent sodium chloride solution Re 6561.5 
(b) 0.05 per cent sodium chloride solution R= 198.5 
(c) 0.5 per cent saponin solution R—=1,033.0 
(d) 25 ce. of (6)+25 ce. of 1 per cent saponin R=" 129.7 
(d) 25 ce. of (b) +25 ce. of 1 per cent saponin Rae= 130.0 
Calculated [from (b) and (c)] for (da), See 1229 
Hence the decrease of conductivity is about 6 per cent or the osmotic pressure 
change would approximately be 0.0456 atmosphere, corresponding to 3.42 cen- 
timeters of mercury or about 40 centimeters of water. 
The change observed is small and, taken in connection with the fact that a 
0.5 per cent saponin+1 per cent sodium chloride solution bursts amebx as 
readily as 0.5 per cent saponin alone, it indicates that the laws of osmosis alone 
probably do not suffice to account for the phenomenon. 
Saponin exerts a similar action upon some flagellates found in tap 
water and stagnant ponds, the motility ceasing, and the organisms swel- 
ling and usually bursting. 
It was noted that air bacteria grew abundantly in a solution of crude 
saponin. A 0.05 per cent solution of purified saponin did not affect the 
motility of cholera vibrios nor retard their growth on an agar slant. 
Agar plates were made from the discharges of a case of bacillary 
dysentery, and at the same time parallel series of plates were made with 
acid and with alkaline agar containing 0.1, 0.5, and 1.0 cubic centimeter 
of saponin. The drug did not affect either the number or size of the 
colonies developing. 
These few experiments indicate that this saponin has toxic properties 
closely resembling those possessed by other substances of the same nature. 
The experiments with amoeb indicate that it acts first upon the outside 
membrane, as was held by Ransom and Stewart, and that the penetration 
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