Typhus Fever and Pedicnlidce 239 



of the second generation were placed on a normal rhesus monkey. 

 The experimenters were unable to keep the monkey under very 

 close observation during the following three or four weeks, but from 

 the fact that he proved resistant to a subsequent immunity test 

 they concluded that he probably owed this immunity to infection 

 by these lice of the second generation. 



Anderson and Goldberger (19126) object that due consideration 

 was not given to the possibility of a variable susceptibility of the 

 monkey to typhus. Their similar experiment was " frankly nega- 

 tive." 



Prophylaxis against typhus fever is, therefore, primarily a ques- 

 tion of vermin extermination. A brief article by Dr. Goldberger 

 (1914) so clearly shows the practical application of his work and that 

 of the other investigators of the subject, that we abstract from it 

 the following account : 



" In general terms it may be stated that association with a case of 

 typhus fever in the absence of the transmitting insect is no more 

 dangerous than is association with a case of yellow fever in the 

 absence of the yellow fever mosquito. Danger threatens only when 

 the insect appears on the scene." 



"We may say, therefore, that to prevent infection of the indi- 

 vidual it is necessary for him only to avoid being bitten by the louse. 

 In theory this may readily be done, for we know that the body louse 

 infests and attaches itself almost entirely to the body linen, and that 

 boiling kills this insect and its eggs. Individual prophylaxis is 

 based essentially, therefore, on the avoidance of contact with indi- 

 viduals likely to harbor lice. Practically, however, this is not 

 always as easy as it may seem, especially under the conditions of 

 such intimate association as is imposed by urban life. Particularly 

 is this the case in places such as some of the large Mexican cities, 

 where a large proportion of the population harbors this vermin. 

 Under such circumstances it is well to avoid crowds or crowded places, 

 such as public markets, crowded streets, or public assemblies at 

 which the 'peon' gathers." 



"Community prophylaxis efficiently and intelligently carried out 

 is, from a certain point of view, probably easier and more effective 

 in protecting the individual than is the individual's own effort to 

 guard himself. Typhus emphasizes, perhaps better than any other 

 disease, the fact that fundamentally, sanitation and health are 

 economic problems. In proportion as the economic condition of the 

 masses has improved that is, in proportion as they could afford 



