SPOROZOA. 



23 



noticed an increase of the white blood-corpuscles and a similar 

 decrease of the red, death possibly resulting in from twenty to 

 sixty days. As much as fifty per cent of the cavalry horses in 

 India have been in some cases destroyed by it, and at Tonquin 

 the French army horses also suf- 

 fered similarly. The Tsetse disease 

 in S. Africa is likewise due to a Try- 

 2'>anosoma in the blood, the Tsetse- 

 fly merely acting as a carrier. 



Balantidum cvU (fig. 4) is one of 

 the Heterotrichae. It is found in 

 the rectum of animals and man. 

 These white ciliata are found free- 

 swimming in the rectal matter. 

 They encyst and pass out in the 

 dung : when the food becomes 

 soiled by the excrement they are 

 again taken into the body in the 

 case of pigs, in which large num- 

 bers are to be found. No harm is 

 done apparently to the pig by their 

 presence. In man a related form 



often produces serious disturbances in Eussia, Sweden, and other 

 parts, but 1 know of no record in Great Britain. 



These are only a few cases of the many Ciliata that are found 

 in various parts of animals. 



Sporozoa. — Another very important group of protozoa para- 

 sitic in both vertebrate and invertebrate animals is the group 

 of Gregarines or Sporozoa (fig. 5). These protozoa are capable 

 of producing serious pathological disturbances, often leading to 

 death. Sporozoa are typically elongate in form, as seen in the 

 family Gregarinidse, the anterior part becoming apparently con- 

 stricted off : this division is not a true one, however, for, as in 

 all Protozoa, these parasites are unicellular. In the most typical 

 cases there is hatched from a spore, called a chlamydospore, 



Pig. 



4. — CiLIATE PrOTOZOON 



(Balantidum coli). 



a, Pseudo-anus ; n, nucleus ; vc, 

 contractile vacuoles ; p, peristome 

 (Stein). (From Par. Dis. Ani., 



Neumann.) 



