196 NATURAL SCIENCE. Sept.. 



medical in its treatment ; it is a study of the worse group of the two 

 groups of fevers of the Roman Campagna : it is entitled " On Summer- 

 Autumn Malarial Fevers," and is by Professor E. Marchiafava and 

 Dr. A Bignami. The second, mainly biological, is on "The Malarial 

 Parasites," and is the work of Dr. Mannaberg, of Vienna. The 

 former is admirably translated by Dr. Thompson, of Washington, 

 who has added an interesting preface of his own : not so much can 

 be said for the translation of the second part of the volume, where 

 misprints, errors in translation, and unintelligible sentences detract 

 from the value of the work. 



The study of the subject has an important bearing on some 

 biological questions. It may be of interest, therefore, to attempt 

 briefly, in non-medical terminology, to summarise some of the 

 results for the benefit of general students of biology. 



The dawn of modern work on the subject began with Heinrich 

 Meckel's (i) discovery in 1847 of pigment in the blood of a dead 

 patient who had suffered from malaria. The significance of this, 

 however, was not seen till, in 1879, Marchiafava and Celli began their 

 brilliant course of investigations into malaria, by proving that this 

 black pigment or "melanin" was formed within the red blood corpuscle 

 from the haemoglobin as a product of disease. The next year the 

 great modern impetus to the study was given by the announcement 

 by A. Laveran (2) that he had seen a flagellate organism in the blood 

 of a patient suffering from malaria, which he maintained was the 

 cause of the disease. From that time the study of the subject has 

 made great strides. Laveran appears to have rather jumped at con- 

 clusions, and these were therefore not accepted at the time by many 

 of the most careful investigators ; thus Marchiafava and Celli 

 dismissed these parasites as merely the products of the decomposition 

 of the blood corpuscles. Nevertheless, the truth of Laveran's main 

 conclusion has been verified, and it is now undoubted that the 

 various types of malarial fevers are due to organisms in the blood. 

 « As in our English ague, the first and most striking feature in these 

 malarial diseases is their recurrence at certain regular intervals. In 

 the old days this could not be properly explained, but it is now known 

 to be due to the fact that the malarial parasites pass through a regular 

 life-history. If the blood of a malarial patient be examined with suit- 

 able precautions, with the best type of modern instruments, it will be 

 found to present somewhat the appearance shown in Fig. I., which is 

 magnified a thousand diameters. There it will be seen that many of 

 the blood corpuscles contain foreign parasitic bodies : these are either 

 small and rounded, and occupy only about a tenth of the corpuscle, 

 as shown in one at the lower margin of the figure. These are imma- 

 ture parasites, and their development may be illustrated by the series 

 shown in Fig. II. Here the round discs represent the blood corpuscles: 

 in a we see the parasite in its most primitive condition, living inside 

 the corpuscle. It feeds upon the material of its host, and secretes the 



