114 . Journal of Agriculture, Victoria. [11 Feb., 1918. 



necessary to cut the heads of the trees hard back to correspond to the 

 reduction of the root system due to the lifting. If this is not carried 

 out the transpiration that is going on through the leaves exhausts the 

 trees before root action can take place, and causes the death of the trees. 

 Tf after cutting back any signs of dryness appear further reduction 

 of the top will be necessary. The failure to reduce the top at planting 

 is one of the greatest contributing factors to the losses that growers 

 have recently sustained when handling their young trees. At Wah- 

 gunyah nursery some very large trees received from America were 

 planted out in accordance with the above directions without the loss of 

 a single one, though they had been many weeks in transit. 



HOME-MADE SHEEP DIP. 



By F . li. Teni'ple, Inspector of Stock. ■ 



Though numerous sheep-farmers prepare their own chemical 

 solutions for the destruction of animal parasites in their flocks, it is 

 questionable whether their doing so is really economical. Roughly 

 speaking, the cost of a standard dipping compound prepared with 

 chemical exactness and expert knowledge of what is most destructive to 

 parasites and their eggs, and least harmful to the animals treated, is less 

 than a halfpenny per head. 



However, many will still prefer to make up their dip themselves, 

 and my present object is to draw attention to the danger of persons 

 carrying out this work without some knowledge of the chemicals they 

 are dealing with. The fact that arsenic — the basis of most poison sheep 

 dips — is on the market in three grades, viz., pure, commercial, and low 

 grade, should be emphasized. 



Arsenic is produced in various places in Victoria, being a by-product 

 saved in the treatment of what is generally known as pyrites, and prior 

 to the war a great deal of our arsenic was ]:)urchased for Germany. 



From my own personal knowledge of the business of manufacturing 

 arsenic I can say that some makers produce a compound containing 98 

 per cent, of arsenious acid, Avhile that prepared by others is of a much 

 lower grade. Herein lies the necessity for precaution. Makers of their 

 own dipping fluid using arsenic should ascertain its strength and prepare 

 a formula for their guidance. It might be that they w^ould form their 

 bases on, say, an assumed 80 per cent, arsenic content when in reality 

 the material used might, perhaps, contain 98 per cent, arsenious acid, 

 and consequently w^ould require a more alkaline matter to provide the 

 necessary solution, otherwise a quantity of free arsenic w^ould remain in 

 the mixture, which would be injurious to the sheep. 



Though I have mentioned only two of the component parts of most 

 poison dip preparations, it is, of course, not suggested that these 

 are the only chemicals whose use requires technical knowledge in order 

 to secure their full benefit. 



To state the case in a few words — It does not pay to be one's OAvn 

 " dip maker " without sufficient knowledge of chemistry for working 

 out quantities. 



