Iodine also apparently had no modifying effect upon serum ana 
phylaxLs. whether dissolved in the serum or injected separately into 
the guinea pig. 
Methemaglobin-producing substances, such as the nitrites, do not 
hmder anaphylaxis. 
Ether narcosis masks the symptoms, but does not prevent the fatal 
issue of a second injection. 
Fiuther attempts to find free antibodies to neutrahze the toxic 
action of horse serum by treating it with the sensitized guinea pig 
serum, and also with the brain substance of sensitized guinea pigs, 
proved negative. 
The specific nature of anapJtyJaxi.s is further shown by various experi- 
ments. For example, guinea pigs sensitized with three separate pro- 
teins, viz, horse senun, egg white, and cow's milk, contaiu three sepa- 
rate anaphylactins in their blood. 
Giimea pigs sensitized with human milk do not react to a second 
mjection of cow's milk. This agaiu iudicates not only the specific 
nature of the anaphylactic reaction, but suggests differences between 
the proteiu matter of human and cow's milk. 
Gumea pigs sensitized with sheep’s milk react to a subsequent iu- 
jection of cow's milk. 
Giiiaea pigs sensitized with dog’s milk do not react to a subsequent 
mjection of cow's milk. 
Guinea pigs sensitized with hen egg white react to a subsequent 
mjection of duck egg white : and guiuea pigs sensitized with duck egg 
white react to a subsequent mjection of hen egg white. The residts 
of similar studies with goose, guinea hen. crane, pigeon, and turkey 
egg albumin are recorded m the text. 
The anaphylactic reaction ia the giiiaea pig, therefore, seems to be 
specific iu the sense that the precipitios are specific. That is. there is 
a group reaction in the proteins of allied species, but no reaction be- 
tween the proteins of widely different species or between proteins of 
widely different origin. 
A substance known as ‘'anapitylactin'' is present in the blood serum 
of sensitized guinea pigs. This substance is not present during the 
period of incubation. 
We have been unable to demonstrate the presence of anaphylactin 
in the blo<xl serum of man. the monkey, and the cat. 
Anaphylactin is present in the blood serum of imnume guinea pigs. 
TJie mechanism of anaphylaxis. — ^We find that congestion and some- 
times hemorrhages may be present in guinea pigs dead of ctnaphylaxis, 
but these lesions are not always apparent, and. furthermore, are not 
specific. 
We were imable to demonstrate fatty lesions in guinea pigs dead of 
anaphylaxis, and know, further, they occur in other states. 
