No. 637] 



IMMUNE SERA 



113 



in dispute. Romer, using the complement-fixation tech- 

 nique, found tliat the serum of adult human beings may 

 possess antibodies for their own lens proteins. Bradley 

 and Sansum, employing anaphylactic reactions, found 

 that guinea-pigs injected with guinea-pig tissue-proteins 

 (liver, heart, muscle, testicle, kidney) develop immunity 

 reactions. Again during the late war, the type of toxic 

 action to which anaphylactic shock conforms was found 

 to exist after extensive injury of the soft tissues. It 

 resulted apparently from the absorption of poisonous 

 substances of tissue origin into the circulation. In fact, 

 various cells and tissues when injured liberate such 

 poisons, and even blood in clotting is kno^ra to acquire 

 a transient toxicity of this type. 



With facts such as these before us, is it not a rational 

 hypothesis to assume that changes in various parts of a 

 body may on occasion influence the representatives of 

 such parts in the germ-cells borne by that body? This 

 appears all the more probable when we recall the facts 

 learned from the study of precipitins and of anaphylaxis 

 that each species of animal has a thread of fundamental 

 similarity underlying the proteins of all its tissues. 

 There is no reason to suppose that germinal tissue forms 

 an exception. The further fact that homologous tissues, 

 though existing in different species of animals,' possess 

 similar chemical characteristics, shows that to get an 

 eflfect there need not be absolute identity between the 

 protein with which the result is obtained and the original 

 antigen. Since this is so, in order to have a lens anti- 

 body affect the germ, there need not be absolute chem- 

 ical identity between the substance of such a tissue as the 

 lens and the germinal constituents of which it is the ex- 

 pression. And if this is true for lens, why not for other 

 tissues? 



The blood-serum of any organism with blood thus af- 

 fords a means of conveying the effects of changes in a 

 parental organ to the germ-cell which contains the ante- 

 cedent of such an organ. As long as there is little 



