140 Journal of the Department of Agriculture. 



of the same lot was fed to animal No. 94, this animal recovered. 

 The effect produced would doubtless depend on the degree of infection 

 of any particular lot of cobs with fungus, but in view of the above- 

 mentioned fact it would appear that the particular idiosyncrasy of 

 the animal was also a determiniag factor. 



The general health of the animals in experiment did not seem 

 to be greatly affected. The appetite was well maintained, and with 

 the exception of a slight degree of diarrhoea iu the earlier stages 

 no derangement of the stomach or intestines could be noted. In the 

 latter stages constipation was present. 



Practically no elevation of temperature was noted, and it Avas 

 on this account, associated with the fact that the appetite was main- 

 tained well throughout, that there was such a slight loss of condition 

 in the animals during experiments. 



The foregoing experiments demonstrated conclusively that the 

 feeding of oxen with mealie cobs infected with Diplodia zea produced 

 a condition in the laboratory experimental animals which was indis- 

 tinguishable from that occurring in cattle which gained access to 

 mealie lands, and it was therefore concluded that the conditions were 

 one and the same. As it was still not possible to say what was the 

 actual exciting cause of the intoxication — whether it was due to the 

 fungus, to the products of its metabolism, or to alterations in the 

 starchy content of the grain on which the fungus was growing — a 

 series of experiments were therefore undertaken to elucidate this 

 point. 



Through the kindness of Dr. Van der Byl a pure culture of 

 Diplodia zea was obtained and a number of preliminary experiments 

 undertaken in order to ascertain under what conditions the fungus 

 could be grown in bulk on maize, etc. 



After some preliminary work it was found that the Diplodia 

 would grow well at 27° C. in Mason's jars filled with sterile crushed 

 maize. The lids of these jars had a half-inch opening drilled through 

 to allow for inoculation of the medium with fungus spores. Growth 

 was allowed to proceed for two months. 



Notes on the Expeeiments. 



Of the three animals which partook of the culture of Diplodia on 

 sterile maize in quantities of 20 lb. 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 remained 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 indis- 

 tinguishable 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 zea grown on sterile maize. 



