532 Journal of the Department of Agriculture. — Dec, 1922. 



i]\e animal. S+ahled liorses liave less blood corpuscles than working' 

 animals, and these again less than race horses in training. Other 

 points of physiological and pathological interest were also in- 

 vestigated. 



Xoduhir Woim Disedse in sheep a])pears 1o be gaining in import- 

 ance in South Africa, and heavy losses are ascribed to it in various 

 parts of the country. The life history of the parasite (Oesophagos- 

 toinum columbianum) has now practically been cleared up. It has 

 been found that the larvae in their third stage bore into the mucous 

 membrane of the irtestine aiid give rise to the nodules to which the 

 <lisease owes its name. They do not remain in the noduies for long, 

 but leave them again in the fourth stage after about six to eight 

 <lays. and complete their development in the lumen of the intestine. 

 Tiiese ol)servations at once reveal the ditiiculty in attempting' to treat 

 the disease, and at the same time indicate the lines that should be 

 followed in conducting- such therapeutic tests. The investigations 

 are being continued, especially along therapeutic lines. 



Scab. — A series of experiments was conducted during the year 

 in connection with the life history of the scab parasite. One experi- 

 ment had the purpose of retesting the infectivity of kiaals. The 

 test was so arranged as to meet all the obje(>.ious of the farmers 

 against previous experiments. The result confirmed the conclusion 

 previously arrived at. Various other inteiesting- experiments were 

 carried out with the acari themselves. A number of dips was also 

 examined, and their action on the acari studied. 



Bloedpens. — This disease was studied wherever opportunity 

 offered itself. Valuable information was obtained, but many points 

 still remain to be cleared up. 



Malta Fever. — Some observations and experiments were started 

 with the object of establishing the distribution of this disease amongst 

 animals (especially goats) in South Africa, and of iutrodu'Mng a test 

 for diagnosing the disease in the blood. This test is now being carried 

 out, and the disease has actually been diagnosed in some goats. 

 The question of the relationship between Malta fever and contagious 

 abortion is now receiving attention. 



Spi/orhaetosu m Figs. — The pathology of this disease was 

 investigated. It wms found that the infectioji is by no means very 

 rare in South Africa. Several cases of spontaneous infection were 

 diagnosed. The disease was transmitted in various ways. The 

 spirochaetes seem to have a predilection for the skin, ihe genital 

 organs, and the lungs. Tlie disease very often runs a mild course and 

 results in spontaneous healing. Therapeutic tests ai'e therefore some- 

 what unsatisfactory. 



(lovsitlde. — Earlier experiments were repeated and ihe conclu- 

 sion confirmed that Vangneria pygmaea is the cause of the disease. 

 The plant appears to be more toxic in the early stages of growth than 

 later in its development. 



KriDipsirkte. — Feeding tests were carried out with various species 

 of Cotyledon. Positive cases of krimpsiekte were produced with 

 (Jofyledon loolLicliii . 



