74 HUMAN INTESTINAL PROTOZOA IN THE NEAR EAST 



(10) Lamblia intestinalis. Reproducing Forms. 

 (Plate II, figs. 1 to 5.) * 



It was suggested by one of us (C. M. W.), who had made 

 observations on these flagellates both in man and animals during 

 a period of many years, that L. intestinalis possibly multiplied only 

 in the encysted stage. This suggestion was put forward because 

 free dividing forms had been constantly looked for, but never found 

 even in animals which were killed and examined for the purpose. 

 It was perfectly understood that this view was at variance with 

 what we know of other intestinal protozoa, but, as L. intestinalis 

 is a parasite of the small intestine, it was thought that forms which 

 encysted high up in the gut might still be liberated under the 

 action of the pancreatic juice a little lower down when division 

 within the cyst had been accomplished. In his criticism of this 

 view (British Medical Journal, June, 1916) Woodcock seems to 

 forget that lamblia lives in the small intestine, and that in order 

 to reach the pancreatic fluid there is no necessity for the cysts 

 to escape from the intestine and be swallowed by the same or 

 another host, as must be the case with protozoa which live only 

 in the large intestine. 



The rarity of dividing forms in the stool may be due to the 

 distance of the lamblia from the rectum, but Woodcock offers 

 no explanation of the fact that direct examination of the small 

 intestine of infected animals fails to reveal dividing forms, nor does 

 he tell us if he has searched for them in this situation. One would 

 naturally conclude that dividing forms existed, and it was only 

 with reluctance after many fruitless searchings that another view 

 was put forward. It still has to be proved that the view is 

 incorrect, though observations we have recently made on the case 

 to be described now show that, at any rate under certain conditions, 

 lamblia may divide as a free-living flagellate. 



A patient was admitted to hospital with diarrhoea and the 

 passage of large quantities of mucus. Examination of the stool 

 revealed lamblia in enormous numbers, the mucus portion of 

 the stool being simply packed with free-living flagellates. The 

 patient was also a carrier of E. histolytica. Films were fixed in 

 Schaudinn's fluid and stained with iron hsematoxylin. The lamblia 

 were beautifully preserved, and examination of the stained films 

 showed all stages of undoubted binary fission. The dividing 

 process, as illustrated in the figures (Plate II, figs. 1 to 5),* could 



* See inset between pages 148 and 149. 



