228 Transactions. — Miscellaneous. 



Although, however, it was recognised that the drainage 

 and cultivation of swampy lands in some places played an 

 important part in lessening the fever, the reason of this was 

 not understood. In equally swampy districts no malaria at 

 all was to be found. In other places where there were no 

 swamps and good cultivation it was prevalent. In some 

 districts of India cultivation seemed rather to increase the 

 unhealthiness of a place in regard to fever ; but, then, the 

 growing of rice necessitated the presence of surface water 

 during certain seasons. It was evident that neither the state 

 of cultivation nor the absence or presence of swampy lands 

 were in themselves a full explanation of the absence or 

 presence of malaria. We now know such influence as the 

 drainage of the land had was due to the destruction of the 

 breeding-places of mosquitos. 



It was noted that very frequently the excavation of earth 

 was followed by a sudden outbreak of malarial fever In 

 Hongkong such an outbreak occurred on one occasion among 

 the soldiery of an English regiment, near whose barracks 

 some excavations were in progress. The same has frequently 

 been noticed in other malarial countries where railway cut- 

 tings or similar works were in progress. The explanation is 

 that these works cause the formation of irregularities in the 

 surface of the ground, in which water collects and forms 

 suitable breeding-places for the mosquitos. Until recently 

 these incidents were regarded as evidence that the fever was 

 due to " emanations " from the disturbed earth. 



What has stood in the way of prevention has been that the 

 essential cause of malaria has not been known. Speculations 

 in regard to it had been very numerous, but no satisfactory 

 explanation had been given ; and, as is apt to be the case 

 under such circumstances, the want of knowledge was cloaked 

 by the use of vague terms expressing speculative theories as to 

 the origin of the disease. 



Malaria is known under many names ; some, such a& 

 " ague " and " intermittent fever," have been given from the 

 symptoms the fever presents. " Malaria " itself is a term 

 expressing merely the opinion that it arose from unhealthy 

 air. Similarly we find the supposed cause named " marsh 

 miasma" or " paludinism " ; of later date is the term " telluric 

 poison," this term coined after its supposed connection with 

 emanations from the soil was brought into prominence. So 

 late as 1886 a standard text-book defines malaria as an 

 " earth-born poison for the most part generated in soils the 

 energies of which are not expended in the growth and susten- 

 ance of healthy vegetation." Analysed, this very vague 

 definition is only an evasion of a confession of ignorance. 

 Under such circumstances there was little hope of coping 





