268 SANITARY NOTES 



ifiiin ijuilwals 



1. The main gudwal must be examined for leakaj^e at least three times a week. As 

 soon as leakage is discovered, the fault must be repaired at once and tlie water dried off 

 the ground. 



2. All inlets to branch gudwals must be properly closed when the channels are 

 not in use. 



3. The water at the ends of main f,'udwals must be cleaned every day, as all the 

 refuse, such as melon skins, -^i-uss, etc., collects at these ends and they are favourite places 

 for mosquitoes breeding. 



4. Fish must be kept in the main gudwals, and the latter must be re-stocked witli 

 fish after emptying and filling. 



Branch (judwals 



5. The beds of branch gudwals must, if possible, be allowed to dry before fresh water 

 is run on to them. If this is impossible it is essential that all pools in these beds be 

 abolished before the channels are refilled. 



{). All inlets to irrigated land must be properly closed when iD-igation is not 

 proceeding. 



7. Grass growing at the bottom of gudwals must be kept as short as possible and, 

 where it is feasible, should be rooted out. 



8. Particular attention must be paid to any brancli gudwal which is above the 

 ground level and hence has a tendency to leak. 



9. Wherever the incoming water tends to scoop out the bed of a gudwal, i.e. at 

 the entrance to branch gudwals, a bed of stones should be laid down. 



Gultivated areas 



10. Care should be taken to see that there are no areas of depression in which water 

 will accumulate and form pools. This is especially important in the case of land on which 

 crops like wheat, barley and sugar-caiie are grown, as the thick growth conceals these 

 places and prevents evaporation. 



It is to be remembered that the soil at the farm in question is what is called 

 Leakages in "weeping," i.e. Contains much salt. This is apt to be dissolved out, and hence leakages 

 the banks of ^^ ^j^^ earthen banks of channels are frequent. At one time I thought I would have to 



channels ^ " 



press for the total or partial abolition of this irrigated area, but since the regulations have 

 been issued and those responsible have been got to take an intelligent view of the situation 

 and to co-operate heartily with the Sanitary Service, I am hound to say that things have 

 greatly improved and, at present, and for some time past, the farm has been well-nigh free 

 of all infection. It is hoped this happy state of affairs may persist,' though I fear we must 

 anticipate more trouble in the summer when a larger quantity of water is available for 

 irrigation and when heavy rains may complicate matters. 



While on this subject I may quote a short but instructive paper by Dr. Gordon, 

 of Messina, N. Transvaal, who comments upon a previous article by Dr. Spencer, of 

 Middelburg. He says : " A valuable lesson to be drawn from Dr. Spencer's article in the 

 February issue of the Transvaal Medical Journal, lies in the illustration it affords of 

 the fact that the term ' cultivation of the soil ' must be interpreted in the sense of scientific 

 agriculture, if cultivation is to be acknowledged as an eradicator of the anopheline. 



" It has been abundantly proved in other countries that nuilaria disappears before the 

 advance of scientific agriculture. Dr. Spencer shows that 'cultivation,' as practised in the 

 districts with which he is familiar, results in the increase of malaria. It is therefore 

 ' It has done so up to the present— end of April, 1911. — A.B. 



