189 



10 per cent, of the total base present in the dip, appear to be of no 

 practical consequence, since they are converted into thiosulphate 

 during atmospheric oxidation. The depilatory action of monosulphide 

 or hydrosulphide is much more violent than that of free hydroxide. 

 Under ordinary circumstances a dip would have to be very badly made 

 indeed before the amount of residual base present could become a 

 source of danger in practical dipping, and if reasonable care is taken 

 in preparation, the possibility of injurious action either upon the sheep 

 themselves, or upon their wool, is altogether ruled out. 



Bedford (Gt. A. H.). Report upon the Dipping Trials carried out with 

 the different Proprietary and Home-made Sheep Dips in South 

 Africa. — Union S. Africa, Dept.Agric, Pretoria, ord & 4th Repts. 

 Director Veterinary Research, November 1915, pp. 163-172. 



Practical trials on a small scale were made with eighteen sheep dips 

 available in South Africa. In the main series of trials two dippings 

 at an immersion period of two minutes, and a dipping interval of nine 

 days, were carried out. The general results showed successful cure of 

 scab in all cases except one, when O'Gorman's dip was used at too great 

 a dilution. At a higher strength this dip would also be effective. 

 A few tests carried out at a shorter immersion period and longer 

 dipping interval indicated that, although such conditions might be 

 effective, they could not be regarded as safe. The effect of the various 

 dips upon the general health of the sheep and upon the skin and wool 

 was not observed to be unfavourable, except in the case of Leach's dip, 

 where obvious intoxication occurred in ten out of twelve sheep dipped, 

 the deaths being probably due to the high concentration recommended. 

 At a lower concentration and with revised instructions for use, this dip 

 would probably be efficacious and innocuous. There was every indica- 

 tion that home-made sulphur dips, if properly used, are both effective 

 and harmless. 



Green (H. H.). Arsenical Dip-Tester. — Union S. Africa, Dept. Agric, 

 Pretoria, 3rd & 4th Repts. Director Veterinary Research, 

 November 1915, pp. 199-214, 5 figs. [Received 12th October 

 1916.] 



This paper describes and figures three forms of a dip-tester costing 

 very much less than the outfits at present on the market. 



OoxDER (R.). On the Transmission of Haemoproteus columbae.^ 

 Union S. Africa, Dept. Agric, Pretoria, 3rd & 4th Repts. Director 

 Veterinarv Research, November 1915, pp. 627-632. [Received 

 12th October 1916.] 



The author's summary of this paper is as follows : — The infectivity 

 of the parasite, Haemoproteus columbae, is not hereditary in the carrier. 

 The parasite develops in Lynchia (Olfersia) capensis only to the 

 ookinete, which, through a double protoplasmic segmentation, loses 

 all its pigment and a part of its protoplasm. So long as the ookinetes 

 are present in the stomach of the fly, transmission of the parasite by 

 the fly is possible. The flies clean themselves from an infection 



