CH. iv] VARIATIONS IN MORPHOLOGY 45 



example, has noted the production of elongated forms of B. coli 

 in urine, with altered reaction to Gram's stain, as a result of 

 the passage of a galvanic current of ^th rn.a. strength for 

 one hour. The modification was produced in B. coli present 

 in the human bladder in a case of cystitis and also in a speci- 

 men of urine outside the body, and it persisted for many 

 months. 



8. Symbiosis may affect morphology. The presence of 

 streptococci in a young culture of B. diphtheriae hastens the 

 appearance of "granular" types of the latter (Denny, 1903). 

 Smirnow (1908) found that symbiosis of B. diphtheriae on 

 culture media with (a) a streptococcus, (b) the meningococcus, 

 and (c) an unidentified bacillus derived from a case of acute 

 rhinitis, led in all three cases to the appearance of coccoid 

 involution forms of the diphtheria bacillus. The experiment 

 in the case of the unidentified bacillus was repeated in another 

 way, the two organisms being grown in the two compartments 

 of a double celloidin sac which was inserted into the peritoneal 

 cavity of a rabbit. In the place of the diphtheria bacillus he 

 found a Gram-positive coccus which, however, on Loeifler's 

 blood serum reverted in 24 hours. A repetition of the experi- 

 ment gave exactly the same result. 



Lesieur (1901, quoted by Clark, 1910) claimed that the 

 pseudo-diphtheria bacillus may assume the morphological 

 characters of the Klebs-Loeffler bacillus as a result of 

 symbiosis with aurococcus aureus. 



9. Growth in the living tissues will sometimes modify the 

 morphology of organisms. Gorham (1901) observed that, as 

 convalescence from diphtheria advances, "granular" types of 

 the bacillus give place to "solid" types, and he attributes the 

 change to the action of the body fluids of the now immune 

 patient. 



Adami, Abbott and Nicholson (1899) describe forms of 

 B. coli, isolated from the liver in normal and diseased animals 

 (cow, sheep, rabbit, guineapig) and in man, which resembled 

 diplococci in many cases, and in others short chains of three 

 or four cocci. Similar forms were obtained from the bile and 

 from ascitic and peritoneal fluids, and were produced on adding 



