82 



several larvae hatched out in each case. Two other lots of .100 

 and 80 eggs respectively were similarly immersed for one minute 

 in a creosote dip; no larvae hatched out, Finally, 300 eggs were 

 immersed in creosote dip for half a minute, and the following 

 day one larva had partly emerged and was not quite dead. 

 Suhsequent examination showed no signs of hatching or 

 movement. 



Theilee (Dr. A.). Inquiry into Dips and Dipping in Natal — Af/nc. 

 Jl. Union of SoiitJi Africa, v, no. 1, Jan. 1913, pp. 51-1)7. 

 and no. 2, Feh. 1913, pp. 249-263. 



In the first article the author gives full details as to the pre- 

 paration of dips and the construction of dipping tanks. Scale 

 drawings are given, with practical advice as to the dipping of 

 various animals, especially cows in calf and horses. One report 

 with regard to the dipping of foals said that the result of dij)- 

 piug every 3 days was "simply marvellous," the farmer in 

 question remarking that in the non-dipping days his foals were 

 all stunted in growth. The question of cost is also considered. 



In the second article the effect of dips upon animals is dealt 

 with, and statistics of accidents and other practical details are 

 given. The author then discusses the question of the extent of 

 tick infestation and says that the area of the farms involved in 

 answers to questions sent out by the Department was 1,144 square 

 miles, roughly one-eighteenth of the area of Natal. They repre- 

 sent various altitudes and conditions of soil and climate, and the 

 returns show that the prevalence of ticks is not affected by mere 

 elevation. Even at altitudes of 5,000 to 7,000 feet the tick infes- 

 tation was stated to be gross, and on the coastal belt some farmers 

 state that there are very few ticks present. The relationship, if 

 any, appears to be rather to the number of cattle on a farm: the 

 larger the herds, the greater the number of ticks. In some 

 instances the absence of ticks is put down to the presence of the 

 red-beaked tick bird. Farms in the middle veld were stated to 

 be badly infested in most instances, and only moderately iu 

 others. In some parts of the low veld, ticks were so numerous 

 that deaths of cattle were attributed directly to this cause. Out 

 of 287 farms infested, only 9 were not fenced, but the author 

 says that the evidence of the value of fencing as a barrier to tlie 

 spread of East Coast Fever is more or less negative. The collec- 

 tion of ticks by means of grazing cattle is not attemi)ted in Xatal 

 to any great extent, and it appears that such a procedure is not 

 necessary. 



Some farmers have adopted tlie plan of keeping cattle away 

 from infected pastures for 18 months and so .starving out the 

 ticks. As a result of observations, it would seem to be necessary 

 in Xatal to dip cattle frequently in order to keep down East 

 Coast Fever, and the author considers that experience again 

 shows that short interval dipping (twice a week or sometimes 

 oftener, and certainly at no longer intervals than 5 days) is 

 necessary for the prevention of this disease in districts where it 

 is very prevalent. A recurrence of the disease has been traced to 



