1 62 Lectures on Bacteria. [ xm. 



Spirillum of cholera vegetates invariably in the intestine of 

 the patient, both in the mucus of the intestine and also, according 

 to some observers, penetrating into the tissue of the mucous 

 membrane. Neither it nor any other Bacteria are found in other 

 organs of those who have died of the disease, according to Koch 

 and most other observers. But Doyen attests its presence in 

 kidneys and liver, and van Ermengem found it in the blood- 

 channel of three of the animals in his experiment before or 

 immediately after death. 



On the strength of the observation that the Spirillum occurs 

 only in the intestinal canal, Koch's view is very generally thought 

 to be highly probable, that it produces a very powerful poison 

 there, and that it is this poison which being absorbed from 

 the intestine causes the severe general symptoms of cholera. 

 If it should be proved that the Spirillum is carried through the 

 body with the flow of blood, this assumption must at least receive 

 some modification, and in any case it still requires more distinct 

 proof. 



As regards its shape, Koch's cholera-contagium appears, 

 when its segmentation is most perfect, in the form of spirally- 

 twisted rods or filaments, closely resembling the Spirilla 

 figured on page 82, and of very unequal length and number of 

 spirals. The filament is about 0-5 \i in thickness, but it is not 

 possible to give the exact measurement ; the width of the turns 

 of the spiral is about the same as the thickness of the filament, 

 or less ; the steepness of the individual turns varies. The fila- 

 ment is composed of segments or segment-cells, which are about 

 as long as a half-turn of the spiral, and each of them, therefore, 

 is a more or less curved rod. A separation of the segments 

 from one another does actually and as a rule take place soon 

 after every division, if the Spirillum is actively vegetating in 

 a gelatinous nutrient substratum (gelatine, agar) or on the 

 mucous membrane of the intestine ; in these places, therefore, 

 the Bacterium takes the form of crooked rods, which are either 

 single or united together into short rows; the shape of these 



