poisoning of cattle by r>//'z.0z>/.4-inffxted maize. 449 

 Notes on the Experiments. 



Of the three animals which partook of the culture of 

 Diplodia on sterile maize, in quantities of 20 lbs. each, two 

 developed symptoms. 



These symptoms resembled those produced by feeding on 

 infected cobs, but the onset after the commencement of feeding 

 was shorter, and the symptoms were much more acute. The 

 period during which clinical symptoms were shown was shorter 

 and recovery more rapid. These differences can be accounted 

 for by the fact that the animals received a large dose of more 

 highly concentrated material than was the case in the cob-fed 

 animals. 



The absence of symptoms in one ox may have been due 

 to a tolerance resulting from an attack in the preceding year. 



Conclusions. 



From these experiments it was concluded that a condition, 

 indistinguishable clinically from that produced by feeding on 

 infected cobs or occurring naturally in infected mealie lands, could 

 be set up by feeding on a culture of Diplodia 2ecc grown on sterile 

 maize. 



Further experiments were carried out to determine whether 

 allied species of fungi (Alucor), grown under similar conditions, 

 would produce similar symptoms, and whether Diplodia zece 

 grown on a cellulose medium would give rise to a similar condition 

 when the medium was fed. 



All these experiments gave negative results. 



General Conclusions. 



( i) That a disease in cattle characterised by inco-ordination 

 of movement and paralysis is set up by feeding on mealie cobs 

 which are infected with Diplodia zea:. 



(2) The cultures of Diplodia sees grown on a sterile maize 

 when fed produce clinical symptoms indistinguishable from those 

 set up by feeding on infected cobs. 



(3) That the intensitv of the symptoms and the mortality 

 depend upon the quantity fed and on the percentage of infection 

 present in the grains. 



(4) That cultures of allied species of fungi gro'vn on nirjze 

 are incapable of setting up similar clinical symptom = . 



(5) That the causal factor is not the fungus itself, but must 

 be looked for in the material which is formed as a re-^ult of the 

 interaction of Diplodia cac during its development in the starcliy 

 content of the maize grains. 



A brief description of the disease as it occurs under \eld 

 conditions is herewith given. 



