858 



SCIENCE. 



[N. S. Vol. XVI. No. 413. 



The toxins to which I have chiefly di- 

 rected your; attention in this lecture are 

 those produced by bacteria. But, as al- 

 ready pointed out, we now know that the 

 animal body has the power to produce spe- 

 cific poisons directed not only against in- 

 vading bacterial cells, but also against all 

 sorts of foreign cells. Following the dis- 

 covery by Belfanti and Carbone in 1898 

 of this capacity in relation to injections 

 of blood a wholly new domain of biology 

 has been opened to experimental research. 

 Attention has been withdrawn for the 

 moment to a considerable extent from the 

 bacterial toxins and concentrated upon the 

 animal cytotoxins. Here new facts and 

 conceptions of absorbing interest have been 

 disclosed in an abundance and with a 

 rapidity which are simply bewildering. 



It was my original design to include in 

 this lecture a consideration in some detail 

 of these animal cytotoxins, but so much 

 time has been occupied with other aspects 

 of the subject that I am compelled to 

 abandon this intention. This is perhaps 

 less to be regretted, inasmuch as I under- 

 stand the main purpose of these lectures to 

 be the presentation of applications to medi- 

 cine and surgery of scientific discovery, 

 and it is precisely this side of the recent 

 work on animal cytotoxins which seems to 

 me in the main not yet ripe for profitable 

 discussion on this occasion. It is true that 

 facts of much scientific and practical in- 

 terest have been discovered by the investi- 

 gations, initiated by Shattock and by Griin- 

 baum, followed by Landsteiner, Ascoli, 

 Eisenberg, Kraus and Ludwig and others 

 concerning the isoagglutinative and isolytic 

 properties of human serums in health and 

 in disease. 



But the really great practical questions 

 in this domain relate to the production 

 of autocytotoxins in the human and the 

 animal body. Wliat is the nature of that 

 very efficient regulatory mechanism under- 



lying the horror autotoxicus (Ehrlich) 

 which prevents either the action or the 

 formation of autocytotoxins in consequence 

 of absorption of our own degenerated and 

 dead cells? Can this protective mechan- 

 ism be overthrown by pathological states 

 and self-generated cellular poisons become 

 operative in the causation of anaemias, 

 hasmoglobinurias, chronic interstitial in- 

 flaramations, uraemia, eclampsia, epilepsy 

 and other diseases? To these and similar 

 important questions the existing experi- 

 mental data seem to me too insufficient and 

 inconclusive to furnish any decisive answer 

 at present. I share, however, the hope and 

 belief of many that here is a field for ex- 

 ploration which, although surrounded with 

 many difficulties, gives promise of discov- 

 eries of a far-reaching and important na- 

 ture. I anticipate that some future Hux- 

 ley lecturer will find in this realm a 

 fascinating theme. 



In this connection may be mentioned 

 the great pathological interest pertaining 

 to the recent investigations of Jacoby, Con- 

 radi and others on the phenomena of self- 

 digestion or autolysis of inflammatory exu- 

 dates and necrotic material within the 

 living body. One can readily convince 

 himself of the energetic action of autolytic 

 ferments by the simple experiment of 

 placing a piece of fresh pneumonic lung 

 in the stage of gray hepatization under 

 chloroform and noting the rapid solution 

 of the exudate, in contrast with the absence 

 of this process in earlier stages of the dis- 

 ease. Conradi finds that bactericidal sub- 

 stances, to which he attaches much impor- 

 tance, are produced in tissues and cellular 

 exudates undergoing autolysis. 



Although my theme relates especially to 

 the bearing of studies of immunity on 

 pathology, it is hardly necessary to say 

 that these studies were primarily under- 

 taken to elucidate the great problems of 

 predisposition and resistance to disease, 



