4 PROTOZOA AND DISEASE 



spirillum-like organisms. For these reasons a short chapter on ticks 

 is included in this volume. 



Some other diseases have been found to be associated with the 

 presence of protozoa. One of these diseases is a little tumour, a 

 recurrent papilloma of the septum of the nose, as described by 

 O'Kinealy. 1 Professor Minchin has relegated to the sporozoa the 

 interesting parasites abundantly present in this affection. 



But what of our measles, scarlet fever, small-pox, chicken-pox, 

 mumps, whooping-cough, and other too familiar infectious and 

 contagious diseases of unknown causation ? In two instances, small- 

 pox and hydrophobia, bodies that are widely believed to be protozoa 

 appear within the cells, and these appearances are now of importance 

 in medical practice, being an important element in diagnosis, and 

 as such they should be studied in every medical school throughout 

 the world ; and this quite apart from any agreement as to whether 

 these bodies are protozoa or not having been arrived at. 



With regard to small-pox, it has now been well established for at 

 least five years 2 that certain hyaline bodies the Cytoryctes variola of 

 Guarnieri that appear in the corneal cells of rodents within twenty- 

 four hours after inoculation with variolous or vaccine matter are 

 specific, and may be relied on for making a diagnosis in doubtful 

 cases of small-pox. Had this knowledge been made general in our 

 profession by instruction given in medical schools, some serious 

 errors of diagnosis would have been avoided. 



With regard to hydrophobia, hyaline bodies (Negri's corpuscles) 

 appear most prominently in the cells of the brain and nerve-ganglia. 

 Negri showed in 1904 that these bodies are as distinctive of hydro- 

 phobia as Plasmodium is of malaria, and he and his assistants have 

 succeeded in establishing the conviction that these ' Negri ' corpuscles 

 are sufficiently characteristic to afford a quick and safe diagnosis 

 of rabies, a preparation obtained by pressing a cover-glass upon the 

 cut surface of the Cornu Ammonis being all that is required. This is 



1 O'Kinealy, Proceedings of Laryngological Society, London, vol. x., April 3, 

 1903. 



2 Since Wasielewski (Zeit. fur Hygiene] proved that Guarnieri's bodies are 

 specific for small-pox and vaccinia. 



