142 Journal of the Department op Agriculture. 



donkeys would not appear to be susceptible, as these animals graze 

 over the same area where cattle are dying of the disease without suffer- 

 ing any harmful results. No cases have been recorded of goats or 

 pigs having been affected. 



Caiuse. — The disease is only found associated with mealie lands, 

 and it is popularly supposed by the farmers of the affected areas that 

 it is caused by feeding on mealie cobs which have lain for some months 

 on the ground. In the experimental investigations mealies which 

 had been subjected to these conditions were found to be capable of 

 producing a similar train of symptoms, and this supports the opinion 

 of the farmers. Examination of the cobs fed revealed the fact that 

 a very great percentage were infected with tne fungus Diplodia zea. 

 Experiment evidence has shown that cultures of Diplodia zea in sterile 

 maize when fed to animals can set up clinical symptoms which are 

 similar to those shown in animals contracting the disease naturally, 

 and further experiments indicate that the results are produced by a 

 substance of, at present, unknown composition formed during the 

 growth of the fungus in the maize grains. 



Time after Exposure at which the First Symptoms are Shown. 



In natural conditions in the veld, cases have been known to occur 

 in six to eight days after the animals were placed in the lands. In 

 the laboratory experiments the shortest time which elapsed between 

 ihe commencement of feeding- on the cobs until the first symptoms 

 were shown was three (hiys and the longest fifteen days. The animal 

 which developed symptoms in three days was a very ravenous feeder, 

 and this may account for the short time which elapsed before 

 symptoms were shown. It may be taken that the development of the 

 symptoms depends on the quantity eaten and the condition of the cobs 

 with reference to their degree of infection by the fungus. 



Symptoms. — The first symptoms noted are lachrymation and 

 salivation accompanied by slight quivering of the muscles of the flank 

 and shoulder. The back is slightly arched, and the animal stands 

 with its legs farther apart than normal. The head is carried low 

 and the ears droop slightly; the faeces are mostly soft, but no 

 diarrhoea is present. In this stage, if the animal is walked, only 

 slight symptoms of inco-ordination of movement are to be noticed. 

 Later, these symptoms are aggravated — profuse salivation and 

 lachrymation are apparent — muscular tremors become general. The 

 coat stares, liack is very much arched, and the animal has a dejected 

 appearance. Progression is slow and the animal only walks when 

 compelled to do so. Symptoms of inco-ordination of movements are 

 evinced by high stepping of the legs. Lateral swaying of the body 

 and sometimes a tendency to progress with the hindquarters bent to 

 one side. The animal falls after walking a short distance, unless 

 supported. These symptoms last for about one or two days, after 

 which the animal is unable to rise without assistance, and when lifted 

 stands with the legs wide apart and the head down, and showing 

 irregular spasmodic contractions of the leg muscles. The tail is 

 flaccid ; on walking the animal knuckles over at the fetlocks of both 

 fore and hind limbs, frequently plunging head foremost on the 

 ground after a short distance. Sensation is retained in the muscles. 

 Rumination is suspended, but the animal feeds occasionally and 



