BY J. BROWNLIE HENDERSON, F.I.C., F.C.S. 143 



state of growth and decay owing to the peculiarly hot and moist 

 character of the climate. 



" In October I suspected that the cause acting so injuriously 

 on the health of the Guides was due to the irritant action of 

 some metallic poison, and surmised that it was some salt of 

 zinc in combination with an organic acid or acids. By a rough 

 application of the usual chemical tests I found in December 

 that the water from each tank, as well as that caught directly 

 from the roof, contained the metal zinc in poisonous quantities, 

 and my deductions were subsequently confirmed by special 

 analysis. 



" Mr. P. J. Burgess, M.A., Government Analyst, Straits 

 Settlements, whose report on this water is attached, reports that 

 the water taken directly from the roof is organically a dirty 

 water and unfit for domestic purposes, while water taken from 

 the tanks is as far as organic impurities go, unfit for drinking. 

 And that the tank water held zinc in solution as the acid car- 

 •^onate, 4-82 parts per million (-34 grains per gallon) in quantity 

 as compared to that taken directly from the roof which held 

 11-15 parts per million in solution. 



"It is thus proved that zinc existed in the water in 

 sufficient amount to cause poisoning, and the medical history of 

 the health of the detachment will prove that to this alone was 

 their illness due. Similar detachments from the Malay States 

 Guides who occupied these barracks used water from other 

 sources. They were under my care in 1898 and 1899. The 

 numbers under treatment for gastro-intestinal complaints were 

 not very large during these two years for this class of native. 



" The present detachment used the zinc-contaminated water 

 from their first arrival in March, 1900, until the end of the year, 

 when its use was forbidden and prevented. After its use was 

 stopped, the number of patients steadily decreased. There have 

 been no new cases of this kind, and the general health has much 

 improved. 



"In 1900, colic, diarrhoea, and a spurious form of dysentery 

 were persistently complained of. The health had never been 

 affected in this way before, as the following records of attendance 

 for this class of case, taken before, during, and after using this 

 water supply will prove : 



" f'rom March to October, 1898, 80 men were under treat- 

 ment for this class of case ; in 1899, for the same months, 58 

 patients. In 1900, during the same period, 219 men, and, at 



