CROSS-INFECTION EXPERIMENTS 99 



They found this in one kitten only, and could not distinguish it 

 morphologically from the common Trichomonas hominis of man. 

 Other reports from Brumpt (1925) and Tanabe (1926), and 

 Kessel (1926a and I928r) record finding natural infections of 

 Trichomonas in kittens. 



Giardia 



Giardia has often been reported from cats, having first been seen 

 by Grassi (1881). Deschiens (1925) gave the name Giardia cati 

 to the form which he found in the cat. Hegner (1925) gave 

 the name Giardia fclis to the parasite which he found in the cat in 

 America, basing his species difference on the length to breadth 

 ratio which he considers makes this organism different from 

 Giardia of the dog and of man. Experimental attempts, thus far 

 reported, to infect kittens v^th human Giardia have been meager. 

 Fantham (1917) reports successful results and Deschiens (1921) 

 also claims to have infected two cats with Giardia from man. Wen- 

 yon (1926), however, records three negative attempts to infect kit- 

 tens with Giardia lamhlia of man. 



The writer has this problem under investigation at present and 

 thus far has been successful in establishing human Giardia in six 

 of eleven kittens. In one series of five kittens the first attempt from 

 the first human case was negative, the kittens being examined at 

 intervals during a period of six weeks following the attempt. 

 Material from Case 2, however, yielded positive results and Giardia 

 became established in four of the kittens, three of the kittens being 

 definitely shown to pass cysts of Giardia. The experimental in- 

 fection remained established in two of the animals for a period 

 of three months, one of the others having been sacrificed early in 

 the experiment and the fourth having met an accidental death. 



The writer has not attempted the use of a duodenal tube in de- 

 tecting Giardia in kittens. It would probably be useful if one were 

 sure that the Giardia infection were restricted to the duodenum. 

 However, this is not always the case, for the writer has found 

 natural infections of Giardia in the jejunum and ileum as well as 

 the duodenum of cats. In the current experiments with Giardia 

 in kittens the writer is adopting the policy of rearing the kittens 

 in the laboratory, and insuring a negative litter by sacrificing the 

 mother. While kittens may be naturally infected by feeding the 

 organisms mixed with their food, yet it is relatively easy to give 



