Mat 24, 1907] 



SCIENCE 



811 



pigs sensitized with horse serum begin to- 

 respond to the toxic effects of the same 

 serum on the eighth day. 



If, however, the sensitized pigs be in- 

 jected with the serum of a horse which has 

 been injected several times with progres- 

 sive quantities of human blood, there is no 

 effect. 



On the contrary, if the sensitized pig be 

 injected with the serum of a horse which 

 has received repeated injections of horse 

 blood rendered heemolytic for human blood 

 (red cells), the toxicity is not only re- 

 stored, but is somewhat more toxic than 

 the normal serum. 



The toxic effect of horse serum is modi- 

 fied by the amount of the sensitizer; those 

 which have received as much as 10 to 15 

 c.e. of serum as a sensitizer, are rendered 

 quite resistant to the toxic dose. When 

 the amount of the sensitizing dose is as 

 much as one tenth the body weight, the 

 pigs are immune. 



The toxic effect of the serum is also in- 

 fluenced by the character of the sensitizer ; 

 for an example: If guinea pigs are sensi- 

 tized by a toxin-antitoxin mixture, they are 

 more susceptible than when given normal 

 or antitoxic serum. 



The toxic effect of a serum bears a rela- 

 tion to the amount given, and is influenced 

 by the body weight. 



Precipitated and dialyzed antitoxic 

 serum is less toxic than the normal, or 

 antitoxic serum. 



Milk was found to be nontoxic to guinea- 

 pigs sensitized with antitoxic serum. 



The Alleged Bole of Intestinal Worms as 

 Inoculating Agents in Typhoid Fever: 

 Ch. Wabdell Stiles/ Ph.D., D.Sc, 



' In making the 2,000 microscopic examinations 

 involved in preparing this paper I have been aided 

 by Past Assistant Surgeon Joseph Goldberger, 

 David G. Willets, Ph.B., and Arthur E. Paterson, 

 Ph.B. 



Chief of Division of Zoology, Hygienic 



Laboratory, U. S. Public Health and 



Marine Hospital Service. 



According to a theory recently advanced 

 in France, intestinal worms (especially 

 whipworms) form the inoculating agent in 

 typhoid, much in the same way that fleas 

 inoculate bubonic plague. The theory is 

 based upon the high percentage of whip- 

 worms reported for the typhoid cases by 

 some authors and upon the fact that in- 

 testinal worms may wound the mucosa; it 

 is assumed that the uninjured mucosa 

 forms an impassable barrier to the bacteria, 

 which, however, may pass through these 

 wounds. The theory claims that typhoid 

 bacilli in the intestines are harmless unless 

 parasitic worms, or some other wounding 

 agents, are present. Accordingly, the 

 treatment and prevention of typhoid re- 

 duces itself essentially to treatment and 

 prevention of parasitic worms, especially of 

 whip-worms. The theory is extended to 

 appendicitis, cholera and certain other in- 

 testinal diseases. 



More recently, the theory is also ex- 

 tended to include parasitic protozoa as in- 

 oculating agents in intestinal diseases, but 

 so far as typhoid is concerned no definite 

 statistical data are presented in support of 

 this extension. As the fresh, warm stools 

 should be examined to test this phase of 

 the subject fairly, and as conditions were 

 not favorable for such examination in the 

 present instance, this protozoan phase of 

 the subject could not be consistently 

 studied in the present report. 



The Washington epidemic of typhoid in 

 the summer of 1906 presented the possi- 

 bility of putting to a practical test the 

 verminous side of this exceedingly alluring 

 theory. The results of the study have 

 failed to confirm the theory, for 92.5 per 

 cent, of the patients showed no infection 



