THE POISON OF THE COMMON GARDEN SPIDER. 171 



which we mean blood-cells deprived of their haemoglobin by swell- 

 ing and then again condensing the blood-cell residues. Ehrlich 1 

 had already (in 1885) pointed out the importance of this true pro- 

 toplasm of the blood-cells, and had termed it " discoplasma " because 

 of its peculiar character. According to Ehrlich, the main function 

 of this discoplasma is to prevent the escape of the haemoglobin, and 

 he therefore ascribed the diffusion of the blood coloring-matter to 

 death of the discoplasma. In agreement with this is the fact first 

 described by Bordet 2 and afterward confirmed by Nolf, 3 that it 

 is the stromata which bind the specific serum haemolysins. We 

 could therefore assume that in our case, in all probability, the arach- 

 nolysin would be bound, if bound at all, by the stromata. 



In this Institute a method for the production of the stromata, 

 which differs somewhat from the one commonly employed, has proven 

 particularly valuable, especially in studying the receptors. With 

 the usual solution of the blood in distilled water, the separation by 

 centrifuge of the stromata condensed with salt is extremely dif- 

 ficult; and even with suitable species of blood only a small yield is 

 obtained. By previously heating the blood we have found that 

 the subsequent centrifugation is made considerably easier (perhaps 

 because of a kind of coagulation of the blood-cells) and that a plentiful 

 sediment of stromata is thereby assured. 



The blood employed is heated on a water-bath at 50-60 C. for half an 

 hour (depending on the species of blood, ox blood 60 C., rabbit and guinea- 

 pig blood about 54 C.) until, dark brown in color, it just begins to become laky. 

 Thereupon the blood, made up to 6 to 10 volumes by the addition of water and 

 shaken, is mixed with so much salt that this amounts to 1% of the total amount. 

 The mixture is then strongly centrifuged. The stromata remain at the bottom 

 of the vessel in the form of yellowish-white masses, and can be washed by 

 repeatedly adding NaCl solution and centrifuging. 



The stromata so obtained have preserved their receptor property; 

 they bind specific serum haemolysins, and also, when introduced into 

 the organism, excite the production of specific hcemolytic immune bodies. 4 



1 Ehrlich, Zur Physiologic und Pathologic der Blutscheiben, Charit6 Annalen, 

 X, 1885. 



2 Bordet, Les Serums hemolytiques, etc., Annales de PInstit. Pasteur, 

 1900. 



3 Nolf, Le Mecanisme de la globulyse, Annal. de 1'Inst. Pasteur, 1900. 



4 It may be recalled that immunization with heated bacteria has been suc- 

 cessfully practiced even from the beginning of the study of immunity. 



