HISTORICAL REVIEW 117 



been encountered in all cases. The differentiation of the forms 

 into two bodies, separated by a line or narrow zone of a sub- 

 stance of different refractive power, may be observed. They 

 possess no active motility, but vibrate more or less rapidly." 



"(3) The dejecta and various organs of a large series of lice 

 have been stained in a similar way and examined for the 

 presence of micro-organisms. Certain groups had been de- 

 liberately infected by permitting the lice to feed upon patients, 

 while others were supposedly normal, having been collected 

 from healthy individuals. Streptococci, staphylococci, and 

 oval bacilli occurring in clusters, and certain solid bacilli, are 

 encountered irregularly and indifferently in the feces and in- 

 testinal contents of both 'normal' and 'infected' lice. Polar 

 staining organisms have been found occasionally in the feces 

 and intestinal contents of 'normal' lice, whereas they are 

 present almost constantly, and often in large numbers, in 

 similar material from 'infected' individuals." 



Ricketts understood fully the fallibility of observations 

 based upon smear preparations stained by Giemsa's stain and 

 made every possible endeavor to eliminate error. His obser- 

 vations upon the occurrence of this bi-polar micro-organism in 

 the blood has never been satisfactorily confirmed, although 

 he estimated the number of "bacilli" as from 300 to 2000 in 

 0.01 c.c. of blood. We have never been able to confirm his 

 results either with blood from Mexico typhus or from our 

 Polish cases. It seems hardly possible that Ricketts saw prep- 

 arations like those studied later by da Rocha-Lima, and others 

 from lice, at least he does not describe the enormous numbers 

 of micro-organisms to be found in typhus fed lice. He gives 

 us only the following in the way of estimate: "In the intesti- 

 nal contents of the 'infected' louse it is occasionally necessary 

 to search three or four minutes before bi-polar organisms are 

 found, but in most instances organisms of this type are much 

 more numerous in the intestine of the 'infected' louse, and 

 fifteen or twenty may be found in a single field." 



Gavino and Gerard (1910 1 ) in the same year confirmed the 

 finding of bacilliform bodies and bi-polar bodies free in the 



