CULTIVATION OF SPIROCH^TES 123 



genie to mice, is probably the smallest spirochsete from the blood, 

 being only 3/1, to 6 //, long. 



Numerous spirochaetes have been recorded from the guts of 

 various mammals, birds, fishes, amphibia and insects. 



CULTIVATION OF SPIROCH^TES. Cultures of spirochaetes have 

 been made with little success or with great difficulty until compara- 

 tively recently, when Noguchi (1912) devised a means whereby he 

 has cultivated most of the pathogenic spirochaetes as well as some 

 Treponemata. 



Noguchi has now cultivated S. duttoni, S. recurrentis, S. rossii, 

 S. novyi and S. gallinannn from the blood ; S. phagedenis 1 from human 

 phagedaenic lesions ; S. refringens* and spirochaetes from the teeth. 



His method is as follows : 



A piece of fresh, sterile tissue, usually rabbit kidney, is placed in a 

 sterile test-tube. A few drops of citrated blood from the heart of an 

 infected animal, e.g., rat or mouse, is added, and about 15 c.c. of sterile 

 ascitic or hydroccele fluid is poured quickly into the tube. Some of 

 the tubes are covered with a layer of sterile paraffin oil, others are 

 left uncovered. The tubes are incubated at 37 C. The best results 

 are obtained if the blood is taken from an animal forty-eight to seventy- 

 two hours after it has been inoculated, that is, before the spirochaetes 

 reach their maximum multiplicative period in the blood. The presence 

 of some oxygen seems indispensable for these blood spirochaetes, and 

 they fail to develop in vacua or in an atmosphere of hydrogen. 



For subcultures, 0*5 c.c. of a culture is added to the medium 

 instead of citrated blood, and it is useful to add a little fresh, normal 

 blood, either human or from an animal, such as a rat. 



Noguchi found that the events in cultures were : 



S. duttoni* maximum multiplication on the eighth to ninth day ; 

 disintegration beginning on the tenth clay, spirochaetes disappeared 

 after about the fifteenth day. No diminution of virulence was found 

 at the ninth day. 



S. rossii ( = S. kochi).* Maximum development on the ninth day, 

 after which the virulence diminishes. The incubation period is also 

 prolonged . 



S. recurrentis 5 (=S. obermeieri). Maximum growth on the seventh day. 



S. novyi. 6 Maximum development on the seventh day. It is 

 more difficult to grow than the preceding forms. 



All the above spirochaetes showed undoubted longitudinal division 

 and transverse division was observed in part. 



S. gallinarum 1 can be cultivated as above, but transverse division 



1 Journ. ExptL Med., xvi, p. 261. 2 Journ. ExptL Med., xv, p. 466. 



3 Journ. Exptl. Meet., xvi, p. 202. 4 Ibid., p. 205. 



5 Ibid., p. 205. 6 Ibid., p. 208. ~ Ibid., p. 620. 



