MALARIAL PARASITOLOGY 505 



denser protoplasmic boundary zone of the corpuscle offers no resistance 

 to the parasite. 



Tlu' technique recommended below shows that the infested cor- 

 puscle early undergoes a granular degeneration, which, curiously enough, 

 in the first few hours resembles the ordinary granular stroma degenera- 

 tion with basic affinity, while it is later seen that the affinity of the then 

 more numerous granules is more acid or at least the staining is no longer 

 orthochromatic, the blue being superimposed by a red; in other words, 

 these granules stain later metachromatically. The greater the loss or 

 transformation of the haemoglobin the greater the number of granules. 

 This holds good only for tertian parasites, the sestivo-autumnal variety 

 causing practically no appreciable change though the same technique 

 be used. 



But the mere recognition of the malarial parasite in the blood is 

 insufficient to-day. Not only should the physician know the variety with 

 which he is dealing, but also it will be to his advantage to know some- 

 thing about the progress which the disease is making by study of the circu- 

 lating parasite. This will seem difficult at first, but a relatively small 

 amount of study will show the value of the recognition of certain changes. 



In tertian fever much can be learned from the study of, let us say, three 

 typical cases, viz. : (1) a recent primary infection; (2) a primary infection, 

 but of long standing; (3) a relapse. The student who knows the forms 

 occurring in the typical recent primary infection will readily observe many 

 morphological differences between these and the parasite of the pro- 

 tracted case. He will then also find at least two forms which are not 

 readily classified with those of his recent primary infection. These 

 forms are the gametocytes or gametes, the analogues of the crescent. 



The microgametocyte of tertian malaria is a large parasite with little 

 affinity for methylene blue, carrying more conspicuous pigment arranged 

 frequently as a wreath around a large achromatic zone in which filaments 

 of chromatin lie. These filaments are the microgametes, also known 

 as the flagella. When living the pigment of this parasite is immotile 

 until just before the parasite flagellates, at which time an unusual 

 activity of the granules is seen. 



The second form is the macrogamete, which is an extracorpuscular 

 body, staining deeply in methylene blue, having a hazy chromatin 

 mass in indistinct achromatic zone usually situated peripherally. 



The young form which grows ultimately into a microgametocyte is 

 ring-shaped, with a heavy chromatin body well within the achromatic 

 zone. 



In relapses a third form is met with which has a compact chromatin 

 body, surrounded by a paler area, that can, however, be stained pinkish 

 by chromatin dyes." The recognition of these forms is of the utmost 

 importance because the prognosis depends upon them. They are quite 

 resistant to quinine and other drugs, and it appears as if cases in 

 which these forms are seen are much more prone to relapse than 

 promptly treated recent primary infections. 



Also the absence of gametocytes from the blood means that no 



