4 DAVID J. DAVIS 



'produced, in animals, and we are therefore handicapped greatly in 

 not being able to apply this method to the study of the disease. There 

 is little doubt but that its cause, as well as that of many other human 

 diseases of unknown origin, would be soon cleared up if only available 

 material for experimentation could be procured. The possibility, 

 however, of an etiologic ultramicroscopic organism should be kept 

 in mind in studying this disease, and methods devised accordingly. 



II. LITERATURE. 



The literature upon the bacteriology of pertussis is as confusing 

 as it is extensive. Almost every year one or more new organisms 

 are described and assigned an etiologic r61e in the disease. Curi- 

 ously enough, many of the investigators find organisms differing 

 from those found by every other investigator, and their enthusiasm 

 has not infrequently led them into controversies of a more or less 

 personal character. After going over the literature one is clearly 

 impressed with the idea that a great deal of rather superficial work 

 has been done on the subject, and very little that is really thorough. 



For convenience it may be well to divide the findings, as Jochmann 

 and Krause have done, into three classes, namely protozoa, cocci, 

 and bacilli, and discuss each briefly. 



Protozoa. Henke 1 in 1874 and Deichler 2 in 1886 found constantly, in the sputum 

 of whooping-cough patients, bodies which they interpreted as protozoa. Kurloff3 in 

 1896 reported similar findings. From the illustrations accompanying his paper one 

 can scarcely draw any conclusion other than that they are desquamated, ciliated 

 epithelial cells. Behla4 in 1898, who also found ameba-like bodies in fresh pertussis 

 sputum and assigned to them an etiological significance, interprets Kurloff's ciliated 

 bodies as epithelial cells, but says that the ameba-like bodies, which Kurloff also 

 described, were the same as his bodies. All of the above results were inadequately 

 controlled and only indefinite data are given concerning the cases examined. The inter 

 pretations, ' f or the most part, have been based upon observations made in unstained 

 specimens. Behla states that staining was of no differential diagnostic value. The 

 usual interpretation given to these results by later investigators is that leucocytes 

 and epithelial cells have been ndstaken for protozoa. 



Cocci. Certain early observations, such as those recorded by Moncorvo, Barlow 

 and Broadbent, Haushalter and Mircoli, are of no significance, and need not be dis- 

 cussed. Ritters in 1892, and later in 1896, described a small diplococcus which he 

 obtained constantly from 146 cases of pertussis, and which he considered the probable 



1 Deutsches Arch. }. klin. Med., 1874, 12, p. 630. 3 Cenlralbl. f. Bakt., 1896, 19, p. 513. 



Baumgarten's Jahresbericht, 1886, 2, p. 347. Deutsche med. Wchnschr., 1898, 24, p. 299 



s Berl. klin. Wchnschr., 1892, 29, p. 1276; also 1896, 33-, p. 1040. 



