448 POISONTNC, OF CATTLE BY D7PLOZ?/.-( "INFECTED MAIZE. 



In the case of this latter animal the feeding was continued up 

 to the time of death. It is considered that, had the feeding 

 of cobs been discontinued when symptoms of improvement were 

 shown, death would not have ensued. In the other animals under 

 experiment no medicinal treatment of any sort was administered, 

 and the recovery in their case is attributed to the fact that, as 

 soon as the first symptoms of paralysis or inco-ordination of 

 movement were first observed, the animals were not given any 

 more mealie cobs. The additional ration of sugar cane which 

 was administered in their case could not be supposed t(^ have 

 any special curative influence other than that exercised in general 

 by the good nursing which was accorded to the cattle. The 

 quantity of cobs fed to the experimental animals was considerable. 

 In the case of Ox No. 87, it was observed that although this 

 animal consumed the smallest quantity, it was followed by fatal 

 result-, and that, although a similar quantity of mealie cobs of 

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

 The effect produced would doubtless depend en 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 determining factor. 



The general health of the animals in experiment did not 

 seem to be greatly affected. The appetite was well maintained, 

 antl. with the exception of a slight degree of diarrhoea in the 

 earlier stages, no derangement of the stomach or intestines could 

 be noted. In the later stages constipation was present. 



Practically no elevation of temperature was noted, and it 

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

 was maintained 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 sea: 

 produced a condition in the laboratory experimental animals which 

 was indistinguishable 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 undertaken 

 to elucidate this point. 



Through the kindness of Dr. van der Byl a pure culture '^f 

 Diplodia sees was obtained, and a number of preliminary experi- 

 ments 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 fruit jars filled with sterile 

 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. 



