THE PATHOGENIC PROTOZOA 179 



The organisms differ from the known flagellates parasitic 

 on animals, and will doubtless be placed in a new genus, 

 for which the name of Phytomonas has been suggested 

 by Donovan. 



The Spirochsetes. 



Authorities are divided as to whether the members of 

 this group should be regarded as Bacteria or Protozoa. 

 The presence of a definite nucleus, blepharoblast, undu- 

 lating membrane, and multiplication by longitudinal 

 division suggest a protozoan nature, but some observers 

 have thought the flagellum to be of a bacterial type in 

 8. recurrentis, and Jordan states that this organism 

 multiplies by transverse fission. 



Spirochseta recurrentis (Spirillum Obermeieri) is an 

 actively motile, delicate, spirillar filament, found in the 

 blood-plasma in relapsing fever during the febrile period. 

 It measures about 8 ^ long and about 0-3 /LL thick, and 

 is pointed at the ends. Monkeys can be inoculated, but, 

 with the exception of rats, other animals are immune. 

 Bed-bugs and pediculi are supposed to transmit the dis- 

 ease. Darling found granular forms in the tissues of 

 animals infected with the spirochsete of the relapsing 

 fever which occurs in the Isthmus of Panama, which 

 granules he suspects to be biogenetically connected with 

 the spirochaetes, and inoculation of such tissue, apparently 

 completely free from spirochsetes, was followed by in- 

 fection. 



Spirochaeta Duttoni occurs in the body of the tick 

 (Ornithodoros moubata). Clumps of chromatin granules, 

 considered by Leishman to be biogenetically connected 

 with the spirochaete, are found in the Malpighian tubes of 

 the tick (Lancet, 1910, i. 12). These ticks, by feeding on 

 a man or monkey, produce tick-fever. 



A fowl spirochsetosis occurs in the Soudan, and is trans- 

 mitted by Argas persicus. Spirochaeta anserina occurs 

 in geese. Fantham, Chalmers, and O'Farrell found^a 

 spirochaote in a form of bronchitis endemic in some^parts 

 of the Soudan. 



Spirochseta pallida, or Treponemal pallidum. This 

 actively motile spiral-shaped protozoonjs very thin and 

 varies from 4 {JL to 14^ in length, with an "average thickness 

 of 0*25 ji. The ends taper. Six to eight spirals are 



