(34) 



toxin into the bloodvessels, the result is, that this is bound and free 

 antitoxin proceeds. Ehrlich explains this as follows. When a toxin 

 is injected, there are most probably cells which contain a group of 

 atoms able to bind that alien substance. Now Weigert has stated the 

 biological law, that when anywhere in the body tissue is destroyed, 

 the gap usually is tilled up with overcompensation. So, it may be 

 assumed, that wiien the cell looses free groups of atoms, so many 

 of these new ones are formed, that they can have no more place 

 on this cell and now come in free state in circulation. This group 

 of atoms is the antitoxin corresponding to the toxin. 



As a special case of this general phenomenon the forming of 

 precipitin is to be considered. 



When a calf is repeatedly injected with horseserum, which can be 

 regarded as a toxic liquid for the calf, then after some time it 

 appears that in the bloodsei'um of that calf an antitoxin is present. 

 In taking some bloodserum from this calf and by adding this to the 

 horseserum a sediment proceeds. This sediment is nothing else than 

 the compound of the toxin of the horseserum with the anti-toxin that 

 had its origin in the body of the calf. We are accustomed to call 

 this antitoxin precipitin, and the toxin here present in the horseserum, 

 and which gave cause to the proceeding of precipitin, precipitinogen 

 substance. The compound of both is called precipitum. 



It is very remarkable that such a precipitate proceeds only, when 

 the precipitin is brought in contact with its oimi precipitinogen sub- 

 stance. Indeed by adding the designed calfserum containing preci- 

 pitin, not to the horseserum but to the serum of another animal, no 

 precipitate proceeds. In this we have also an expedient to state if in 

 a liquid (e.g. an extract of blood stain) horseserum is present or not 

 (Uhi.enhuth, W^assermann inter alia). Meanwhile such a calfserum 

 gives notwithstanding also a precipitum with serum of the ass related 

 to the horse. 



To the same phenomenon the fact is to be brought, that when 

 a i-abbit has been injected with oxenserum, the serum taken from 

 the rabbit does not only give a precipitate with oxenserum but also 

 with that of the sheep and the goat, which are both related to the ox. 



Some time ago an expedient was given to distinguish also ') serum 

 proteid from rehited species of animals by a quantitati\'e way, and 

 in connection with this a method ^) was proposed to determine accu- 



1) H. J. Hamburger, Eine Matliode zur Differenzirung von Eiweiss biologisch 

 verwandier Tliierspecies. Deutsche Med. Wochenschr. 11)05, S. 212. 



") H. J. Hamburger, Zur Untersuchung der quantitativen Verhaltnisse bei der 

 Pracipiüureacliüii. Folia haemalologica. 11 Jahrg. N". 8. 



