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Chapter XXV 



GENUS HAEMOGREGARINA 



The haemogregarines are unfigmented parasites 

 mostly found in the blood of cold-blooded vertebrates, 

 but also in that of a few mammals. They are endo- 

 globular parasites ; but with a free vermicule stage. 

 The great majority attack the red blood corpuscles; 

 but certain of the mammalian forms attack the 

 leucocytes. They are, so far as is known, non-patho- 

 genic, and they cannot be transmitted by inoculation 

 from one animal to another. Schizogony not in- 

 frequently takes place in the cells of some viscus, liver, 

 kidney, bone marrow, etc. The sexual cycle of 

 development has only been described in a few cases 

 and cannot yet be said to be definitely known. 



According to some authors three kinds of haemo- 

 gregarines exist in the blood, thus Prowazek, in H. 

 platydactyli, describes : 



Indifferent Forms. The nucleuses rich in chroma- 

 tin and stains very deeply. The protoplasm is dense and 

 filled with red staining matter (Romanowsky). These 

 forms frequently leave one red cell and enter another. 



Female Forms. Broader than the former, and 

 frequently found expressed from the cell. 



Male Forms. Slender, with a chromatin rich 

 nucleus, the protoplasm staining a light blue. They 

 often contain a blepharoplast. The males are often 

 vacuolated. The red cells are often bent by the 

 movements of the parasite, and in stained films are 

 boomerang or banana shaped. 



Technique. Examine the blood of warm and 

 cold-blooded animals. For schizogony make sections 



