200 NATURAL SCIENCE. Sept., 



in the same way ; it therefore acts only when the parasites are 

 passing through the stages of nutrition and development. When all 

 the haemoglobin of the corpuscle which acts as the host has been 

 converted into melanin, the parasite ceases to grow, but divides into 

 spores for reproductive purposes, and quinine becomes powerless. It 

 is therefore necessary to take quinme in the intervals between attacks of 

 fever, and useless to do so when the pyrexia is at its worst. This 

 was long ago determined empirically by tropical practitioners, who 

 also understand that quinine really does as much harm as good if 

 taken at the wrong time. The reason for this also is now explained, 

 for Binz has also shown that quinine has an unfavourable action on 

 the leucocytes, or white corpuscles, which are thus checked instead 

 of being aided in their struggle with the disease. Thus an unintelli- 

 gent use of this reagent may be attended with very unfavourable 

 results. This is likely to happen as many of these malarial para- 

 sites are not checked by quinine : this is the case with those which 

 cause malarial fever in birds, and with some forms of human para- 

 sites. For instance, those shown in Fig. III., and known as the 

 " crescentic bodies of Laveran," are quite uninfluenced by this 

 reagent. If microscopic examination be neglected, and quinine 

 administered in strong doses under the idea that the fever is produced 

 by the species illustrated in Fig. I., serious injury may result. 



The researches embodied in these two monographs are of 

 the highest interest, both to the biologist, from the detailed investi- 

 gation of the life-history of these low Sporozoa, and to the doctor, 

 from their guidance in the proper treatment of a very troublesome 

 and obscure group of diseases. 



EXPLANATION OF FIGURES. 



I. — Blood infested by malarial parasites (after Mannaberg), magnified 1,000 dia- 

 meters. It shows (i) normal red blood corpuscles (the round discs with 

 white centres) ; (2) a normal white corpuscle or leucocyte (the large 

 dark circular mass touching the lower right hand border of the figure) ; 

 (3) red corpuscles infested by the parasite in its youngest stage (two shown 

 one above the other, in the middle line, just above the lower margin of the 

 figure) ; (4) red corpuscles almost fully developed (the large discs contain- 

 ing shaded bodies) ; (5) parasites in which spore formation has commenced 

 (one occurs in the upper part of the figure, a little to the right of the 

 middle line ; it is a dark body, roughly oval in form.) 



The hjematozoa belong to a tertian form. Thus, as spore formation is just 

 beginning (as shown by the large size of most of the older generation of 

 parasites, and that in two spore formation is fairly advanced), the patient 

 is approaching an immediate paroxysm of fever. As a second generation 

 is also present this will cause another attack of fever next day, so the 

 patient is suffering from a " double tertian fever." Quinine if taken now 

 would kill the parasites of the second generation, have no influence on the 

 older generation, and check the efforts of the white corpuscles and of the 

 phagocytic cells in the spleen to eradicate the disease. 



II. — a-o, the life-cycle of the hasmatozoa of a quartan fever. (After Marchiafavaand 

 Bignami). In a-1 the parasites are shown in red blood corpuscles. In a 

 the parasite is in its simplest unpigmented condition ; b-i show the gradual 



