HERPETOMONAS 565 



tract of man. It is particularly found in chronic diarrheas, but it 

 is not pathogenic. Prowazek found a similar trichomonas in monkeys 

 and other animals. 



Lamblia Intestinalis . This is another organism of the order poly- 

 mastigina, and is found in the intestines of mice, rats, dogs, cats, 

 sheep, and rabbits, and occasionally of man. The organism is beet- 

 shaped and bilaterally symmetrical. It is 10 to 21 micra long, 5 to 

 12 micra wide ; the flagella measure from 9 to 14 micra. At the anterior 

 end the organism possesses a kind of sucking concavity, the margins 

 of which project and appear to be contractile. It has four pairs of 

 flagella, arranged one pair as anterior, one pair as posterior, and 

 two pairs as lateral flagella. The posterior portion of the body forms 

 a tail 2 to 2J micra long, from which the posterior flagella project 

 outward. The nucleus is bilaterally symmetrical, and each half is 

 oval in shape, each side generally contains a deeper staining nucle- 

 olus-like body. The protoplasm is densely hyaline and surrounded 

 by a kind of external pellicle. Contractile vacuoles are not present. 

 The exact mode of division is unknown, but cysts surrounded by 

 a chitinous membrane and possessing four nuclei have been observed. 

 Infection of men and animals is brought about by ingestion of the 

 cysts. Grassi has demonstrated this mode of infection by swallowing 

 cysts. Lamblia in the intestines fastens itself by the sucking apparatus 

 at its anterior end to the intestinal epithelia. The organism, however, 

 does not appear to be pathogenic. Parts of the intestines where 

 numerous lamblia are attached do not show any pathologic changes. 



L. Pfeiffer found numerous trichomonas-like protozoa in the 

 intestines of chickens, ducks, and other birds suffering from diarrhea 

 with diphtheritic inflammatory changes in the intestines. It has, 

 however, not been conclusively proved that these trichomonas, or 

 lamblia, were the cause of the intestinal pathologic changes and the 

 death of the fowl. 



Herpetomonas. Herpetomonas, which are nearly related to the 

 cercomonas on one side and to the trypanosomes on the other, are 

 described by Kent as free swimming, elongate or vermicular, highly 

 flexible; the posterior extremity, often the most attenuate, but not 

 constituting a distinct caudal appendage; flagellum single, terminal. 

 Herpetomonas are intestinal parasites of flies and other insects. 

 The best-known species is the Herpetomonas muscse domes tica, 

 the intestinal parasite of the common house fly. It has been studied 

 by Prowazek, who, according to Calkins, describes it as follows: 

 "This organism is elongate and somewhat flattened at one end, 

 which gives rise to the single, long, vibratile flagellum. Apart from 

 the nucleus and blepharoblast the inner protoplasm has no char- 

 acteristic structures, and the nucleus is of the characteristic masti- 

 gophora type, with chromatin granules of more or less definite number. 

 The blepharoblast lies between the nucleus and the flagellum, and is 

 frequently of large size, while from it the base of the flagellum takes 



