1915] Poisons of Plant-Lice 345 
takes place even at ordinary temperatures with the undiluted 
extract, as shown in the following example: 
An extract was manufactured by triturating 0.5 gr. of 
plant-lice in 5 ccm. of a mixture of physiological salt-solution 
and glycerine in equal parts. In the dilutions of the extract 
used 1 cm. of physiological salt-solution contained the fol- 
lowing amounts of extract: 
1. 1lccm. phys. salt-solution contained 1/12.5 ccm. Extr. 
eve tle ioe . - 2 25 ccm. Extr. 
3. 1 “ “ “ “ 1/50 “ “ 
ah. 1 “ “ “ “ 1/100 “ “ 
5. 1 “ “ “ “ 1/200 “ “ 
1 ccm. of the diluted extract was mixed with 1 ccm. of the 
5 per cent blood dilution. Nos. 1, 2 and 3 gave complete 
hemolysis. In No. 4 a small portion of the blood-corpuscles 
remained undissolved and in No. 5 the hemolysis was incom- 
plete. In the control tubes no hemolysis occurred. 
From this experiment and from another performed with 
the same sample of extract, which gave the same results,. 
it is possible to make the following computations concerning 
the hemolytic effect of plant-louse poison on the red blood 
corpuscles of the ox. 
In 5 ccm. of extract there were 0.5 gr. of plant-louse matter 
oF Usinst= tomlucem: (of extract. In, 1/200) cem-“on extract there 
was therefore 0.0005 gr. of plant-louse matter. This 0.0005 
gr. brought about a partial solution of the red corpuscles in 
1 ccm. of a 5 per cent dilution of blood or the solution of the 
red-corpuscles of 0.05 ccm. of the undiluted blood of the ox. 
A complete solution of the red-blood corpuscles of 0.05 ccm. of 
the undiluted blood of the ox did not, however, take place 
till 1/50 ccm. of the extract or 0.002 gr. of plant-louse matter 
was used. In other words, 1 gr. of plant-louse matter will 
completely dissolve the red-blood corpuscles of 25 ccm. of 
undiluted blood or 40 gr. will dissolve a litre of blood. 
The hemolytic power of ‘‘aphidolysin,’’ as we may call the 
substance, is therefore weaker than the poison of the house- 
spider (‘‘arachnolysin’’),* since 0.000028 gr. of this substance 
completely dissolves the red blood corpuscles of 0.05 ccm. 
of the undiluted blood of the rabbit (i. e. 1.4 gr. dissolves 
*Hans Sachs Joc. cit. 
