296 



DISEASES CAUSED BY SPIRILLACEAE 



of the red corpuscles show a slight irregular motion, and when 

 closely watched it may be noticed that this disturbance may 

 proceed in a certain direction, or again whirl round in the 

 same place. When examined under a high power (i-i2th 

 inch obj.) the agile spirillum is usually seen attached to one or 

 more red corpuscles. Sometimes it is curled all round a red 

 or white corpuscle. As soon as the organism becomes free 

 and begins to travel through a clear space, a characteristic 

 undulating movement is visible, which continues until it finally 

 attaches itself to some other blood corpuscle. This motion 

 may be noticed for some time ; it then becomes relaxed, and 

 finally slackens down completely. I have observed the 

 movements in preparations which were twenty- four hours old. 

 "Staining of the organism ma}^ be obtained with an}' of 

 the aniline dyes used in bacteriology, viz., methylene- blue, 

 fuchsin, thionin. Good preparations were obtained with 

 lyaveran's modification of Romanowsky's stain, and also with 

 Azur II. In using the last two mentioned methods no chro- 

 matic bod}' could be traced, such as is present in parasites 

 belonging to the protozoa. 



"Cultivations on the 

 usual artificial mecia were 

 repeatedly tried, but al- 

 ways with negative results. 

 The same has been found 

 to be the case with all the 

 above-mentioned different 

 spirilla found in men and 

 birds. " 



§ 224. A disease of 

 the pig due to spiro- 

 chaetes. Dodd has recently 

 described a spirochaete 

 which he found in a pig 

 sent to the government 

 laboratory in Pretoria. The 

 examination showed very few morbid changes in the tissues 



Fig. 68. Spirochaetes frotn the lesions 

 in the skin of a pig {after Dodd). 



