CUM A TOLOGY—MTIOLOG Y 



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in 1918, found a streptococcus, while Coles has suggested that more 

 than one germ may be the causal agent. 



In 19 16 Futaki, Takaki, Taniguchi, and Osumi discovered a 

 spirochsete in the lymph glands and pathological products of patients 

 suffering from the disease. In the same year Costa and Troisier 

 reported cases in France. 



Climatology. — ^As the rat is widespread, so the disease is found in 

 many parts of the world, being recorded in Japan, China, Ceylon, 

 India, Dutch Indies, East Africa, England, France, Italy, Balkans, 

 Holland, Germany, and North and South America. 



etiology. — Futaki and his collaborators, in 1916, reported the 

 presence of a spirochaete 9-10 microns in length in the lymph glands 

 and in the tissue fluid from the bitten area. Later they found in 

 man and inoculated animals shorter and thicker spirochsetes 

 2-6 microns long, with regular close steep waves and a filament at 

 each end. Ishiwara, Ohtawara, and Tamura, in 1916 and 1917, 

 in investigations with regard to experimental rat -bite, found spiro- 

 chaetes morphologically identical with the short forms described 

 above, and Kitagawa and Mukoyama, in 1917, found forms measur- 

 ing 6-10 microns in length, with a smaller one measuring some 

 4 microns and a larger measuring 12 microns, in their inoculated 

 guinea-pigs. 



In 1917 Kaneko and Okuda, in performing a post-mortem on a 

 case, found: — 



1. Long spirochcBtes , 6-10 microns in length, with numerous small, 

 steep, irregular waves, identical with Fu^aki's long spirochaete. 



2. Short SpirochcBtes, 17-5 microns in length, with two to six 

 steep, close, regular waves, identical with the short spirochaete of 

 Ishiwara and Futaki, and also to the spirochaetes found by Ido and 

 his collaborators in guinea-pigs bitten by rats and so infected. 



These short parasites have been found by Ido and others in human 

 blood films taken at the height of the disease. Kaneko and Okuda 

 found the spirochaetes in the kidney in casts in the straight tubules, 

 the canals of Henle, and the intercalary portion of the boundary 

 layer. They have also been found in the cortical cells of the supra- 

 renal capsules and in an interstitial space in the testicles, but not 

 in other organs. 



The long and the short spirochaetes belong to the same species, as 

 is proved by pure cultures. The long spirochaetes are considered to 

 be old forms, and are exclusively found in human tissues. The short 

 spirochaetes are the typical young forms, and can be found in the 

 blood of patients suffering from rat -bite fever, as well as in experi- 

 mental animals. In no instances have they been found in healthy 

 guinea-pigs, white rats, or mice. They are absent from the blood 

 and tissues of infected animals receiving salvarsan treatment. 



Ido, Ito, Wani, and Okuda have demonstrated that the serum of 

 persons who have recovered from the disease cont ains an immune body 

 which destroys S. morsusmuris , as demonstrated by Pfeiffer'stest and 

 by the fact that the guinea-pigs employed for this test remain well. 



