qo Phylum Protozoa 



samples from the cecum, where intestinal Protozoa seem to be almost 

 entirely localized, without killing the birds or resorting to surgical opera- 

 tion. The contents of the cecum are evacuated from time to time and 

 this material may be distinguished easily from the intestinal contents 

 passed in the form of feces. The fecal material is usually compact and 

 dark in color, whereas the cecal contents are more liquid and yellowish 

 in color. The best way to obtain cecal material seems to be to give the 

 chicks fresh food and water early in the morning and then place them 

 under glass dishes on paper towels. Here they may easily be watched 

 until cecal material is passed. Some of the chicks will not evacuate 

 their cecal contents for several hours, but most of them will deposit the 

 desired material within a few minutes. 



The method of procedure followed was usually as follows. The Pro- 

 tozoa to be inoculated were obtained either from cultures grown in test 

 tubes or from fecal material. If from the former, a more concentrated 

 inoculum was sometimes prepared by centrifuging the culture medium 

 and pouring off most of the supernatant fluid. If the trophozoites of 

 Protozoa were located in fecal material, this mass was diluted with 

 normal saline solution and passed through cheesecloth to remove all 

 coarse particles that might otherwise clog the passage through the tube 

 used for inoculation. Protozoan cysts may be secured in large numbers 

 by any of the concentration methods devised for this purpose. A simple 

 method is to stir up the infected material in several liters of water in a 

 tall, narrow cylinder; allow the cysts to settle to the bottom, which re- 

 quires about 30 minutes, then pour off most of the supernatant fluid, fill 

 the cylinder with water, stir thoroughly and allow the cysts to settle 

 again. After this has been repeated several times the cysts are well 

 washed and concentrated. 



A s cc. Luer syringe to which was attached a rubber catheter shortened 

 to a length of about 10 cm. was used for inoculating material into the 

 chicks. Most of the chicks were about 4 days old, although older birds 

 were used for studies of age resistance. The amount of inoculum de- 

 pends on the age (size) of the chick. From 2 to 4 cc. of material may 

 be injected into the crop of a 4-day-old chick by lubricating the catheter 

 with vaseline, inserting it down the throat with one hand while the bird 

 is held in the other, and then slowly pushing down the plunger of the 

 syringe. Similarly from 1 to 3 cc. may be injected into the rectum. The 

 catheter should be inserted about 2 or 3 cm. The anal opening should 

 be held closed with the fingers for a few seconds after the catheter is 

 removed. Material injected into the rectum appears to find its way 

 immediately into the cecum. 



The results of introducing intestinal Protozoa from man and other 

 animals into chicks have been prepared for publication elsewhere 



