460 H^EMOLYSINS AND ALLIED BODIES 



Kyes ( 6 ) has, however, shown that the serum-free erythrocytes 

 of certain animals (e.g. guinea-pig, man, dog, &c.) do undergo 

 haemolysis with cobra venom alone, the complement in this case 

 being furnished by the erythrocyte itself (i.e. by endo -complement) ; 

 and further, that a solution of such erythrocytes in isotonic salt 

 solution can furnish the necessary complement, and so produce 

 haemolysis when added to a mixture of snake venom and comple- 

 ment-free erythrocytes (e.g. those of ox, sheep, goat, &c.). 



Various insect poisons (obtained from the stings) can produce 

 haemolysis (e.g. of man and dog) when added to the blood of 

 certain animals, whereas when added to other bloods no haemolysis 

 follows. This is thought to be due to the fact that the serum of 

 these latter bloods contains anti-bodies. Further work on this 

 group of haemolytic substances seems to be wanting. 



From toads a very active haemolysin, especially active towards 

 the erythrocytes of the sheep, can be obtained by grinding the 

 skin with sand in a mortar and extracting with isotonic salt 

 solution. Such a solution can produce haemolysis in a dilution of 

 1 in 10,000. This haemolysin, like others, is inactivated by heating 

 to 56 C., but it cannot be reactivated by adding the serum of 

 higher animals. Proscher ( 5 ) has, however, succeeded in obtaining 

 an antitoxin, by repeated injection into rabbits. 



The poisonous secretions of spiders also produce marked 

 haemolysis, especially of rabbit's erythrocytes. For example 

 the haemolysin of 1-4 grm. of spiders can haemolyse 2- 5 litres of 

 rabbit's blood. The haemolytic agent in this case is called arach- 

 nolysin. For purposes of examination, it can be easily obtained 

 by extracting ground-up spiders (Epeira diadema) with isotonic 

 salt solution. A very interesting fact concerning arachnolysin is 

 that it has absolutely no action on the erythrocytes of the guinea- 

 pig. It cannot even combine with the erythrocytes of this animal ; 

 for, if a mixture of arachnolysin and guinea-pig's erythrocytes be 

 allowed to stand for some time and then centrifugalised, the 

 supernatant fluid will be found to be, quantitatively, as haemolytic 

 towards rabbit's erythrocytes as before. Hans Sachs ( 5 ) has, how- 

 ever, shown that anti -bodies can be produced by inoculation of 

 arachnolysin into a guinea-pig ; as well as into a rabbit. These 

 anti-bodies produced in the guinea-pig must therefore be derived 

 from some tissue outside of the blood. In other words, the extra 

 vascular tissue must possess receptors capable of fitting the 

 haptophoric group of arachnolysin. That the arachnolysin anchors 



