442 VETERINARY BACTERIOLOGY 



morphologically, with resultant liberation of small bodies which 

 stain like chromatin. These are of various shapes rods, cocci, 

 or spirals. They enter the lining cells of the malpighian tubules; 

 they are found in the oviduct, the ovary, and the immature eggs, 

 and in all stages of development of the young tick. Inoculation of 

 material containing these bodies, but not true spirochetes, resulted 

 in the development of tick-fever. The details of this life-history 

 are in present need of elucidation. It has been claimed by Mar- 

 choix that the virulence of the spirochete of fowl septicemia can 

 be preserved only by passing through the body of the tick which 



transmits the disease. Con- 

 tinual transfer of the organ- 

 ^ ism from one fowl to 



another, without the inter- 

 mediation of the tick, causes 

 a gradual decrease in viru- 

 lence. This would seem 

 to indicate that a part of 

 the life cycle of this organ- 

 ism must be passed in the 

 body of the intermediate 

 host or tick. None of this 

 group of organisms may be 



,-,. cultivated uponthe common 



.frig. 195. Spirochceta obermeieri show- 

 ing flagella distributed over the body of laboratory media, and they 

 the organism (Frankel). can be induced to multiply 



in vitro only under very 



special conditions. All these facts would seem to mal^e out a 

 strong case for those who believe in the protozoan relationships. 



There are, on the other hand, investigators who believe quite 

 as firmly that these organisms are bacteria. Novy and Knapp 

 studied with great care a spirochete of relapsing fever. They 

 concluded that division was always transverse, and that the 

 longitudinal divisions reported by others were accidental associa- 

 tions or intertwining of two organisms. Their results with the 

 use of plasmolyzing agents received an interpretation quite the 

 reverse of other investigators. Experiments in immunization, 

 the resistance to heat, stability of form, and staining qualities of 



