332 NATURAL SCIENCE. November. 



of malaria. The case was there stated for the behef that this malady 

 is due to the presence of a parasite, which attacks the corpuscles of 

 the blood ; the life-history of this parasite was summarised so far as 

 it was known, its biological affinities were indicated, and the action 

 of quinine upon it was explained. Having given space for a definite 

 exposition of the parasitic theory, we are bound to call attention to a 

 new work, in which the case for the opposite view is stated in great 

 detail. 



The volume is the work of a man who has devoted much time 

 and trouble to the study of this subject. As a research student for 

 the Grocers' Company he went to Italy in 1883, and spent three years 

 investigating the disease and the conditions under which it flourishes. 

 He worked in the medical laboratories of Rome ; he studied the 

 geology, hydrology, and meteorology of the infected areas ; he treated 

 cases medically, and noted the effects of food and drugs on the course 

 of the disease. He seems to have spared no pains, and with the 

 courage of his profession never hesitated at serious personal risks. 



His book is divided into three parts, dealing respectively with the 

 distribution of malaria, with the meteorological and other factors which 

 control it, and with the phenomena of the disease. The author first 

 dwells on the great importance of the subject, illustrating his remarks 

 by the facts that in India half the military forces are temporarily 

 disabled by disease every year, and that the expense of the adminis- 

 tration of that country is greatly increased by the lessened efficiency 

 of individuals. The next two chapters state the distribution of 

 malaria in the world, and especially in Italy. The author then 

 treats of the Roman Campagna in detail, describing its physical 

 geography, geology, and hydrology, and the history of malaria in 

 the province from the earliest records downward. In the second 

 part he gives the result of his investigation into the conditions 

 under which malarial fevers exist, and the circumstances which 

 modify them. He claims that " the only relation of malaria to altitude 

 consists in the diminution of temperature which accompanies the 

 latter " (p. 99), and points out the intimate relationship between 

 malaria and wet soils (p. 109). He attaches great importance to the 

 effect of subsoil water, and maintains that " the intensity of the 

 disease increases as the subsoil water approaches the surface." He 

 refers to localities such as the Amazon Valley, which he accepts as 

 non-malarial, although, according to popular ideas, they ought to be 

 infested with the disease. 



Considerations such as these lead to the argument in the third 

 part of the book. The author there contends that the disease is the 

 direct effect of sudden changes of temperature ; he claims that the 

 parasitic theory is " utterly unsatisfactory," and that the " chill 

 theory " is sufficient to explain all the facts. He ingeniously argues 

 that there is a normal periodicity in the human temperature, and that 

 in malarial fever there is simply an exaggeration of this, produced by 

 chills upsetting the normal relations of the heat-producing and heat- 

 dissipating processes of the body. The liability to a recurrence he 

 explains as due, not to haematozoa persisting in the marrow-cells or 

 in the spleen, but to the patient having acquired, "from some 

 unknown cause, a periodicity of function." 



This third part of the book is the least satisfactory ; the author 

 does not disturb our faith in the parasitic theory, nor does he bring 

 the chill theory into harmony with all the known facts or render it 

 capable of explaining the phenomena of the disease. To take, for 

 example, one illustration of the effects of violent changes of tempera- 



