3^28 



PARASITES OF THE DOMESTIC ANIMALS 



diarrhea, and anaemia. Toward the end weakness has so far advanced 

 that the affected birds are completely helpless and lie with their heads 

 upon the ground. Those which survive are said to be immune to fur- 

 ther attack. The spiroochete sometimes penetrates the red blood 

 cells; it has also been found in the eggs and in the embryonal epithelium 

 of the chick. 



It is not known with certainty that the disease exists in this country. 

 It is not unlikely, however, that some of the as yet obscure diseases 



Fig. 170. — Hen suffering from acute spirochetosis (after Crawley, from Balfour, Cir. 

 No. 194, Bu. An. Ind., U. S. Dept. Agr.). 



of poultry may be found to be due to members of the spirochete group, 

 — a sufficient reason for mentioning the Brazilian spirochetosis here. 



Order II. Trypanosomatida 



Flagellata (p. 326). 



A number of classifications have been proposed for these organisms, 

 Salmon and Styles placing them in the order Monadida (Moore, 1906). 

 Calkins (1909) classifies them as follows: Subphylum Mastigophora; 

 class, Zoomastigophora; subclass, Lissoflagellata; order, Trypanosoma- 

 tida; typical genera, Tiypanosoma and Trypanoplasma. The same 

 author thus describes the order in tabulation: "Organisms of elongate, 

 usually pointed form, and of parasitic mode of life; with one or two 

 flagella arising from a special "motor" nucleus, and with an undulating 

 membrane provided with myonemes running from the kinetonucleus 

 to the extremity of the cell; one of the flagella is attached to the edge 



