270 Agricultural Gazette of N.S.W. [April 3, 1920, 



Merino, showed distinct reddening of the unprotected pink portions of the 

 skin, notably on the nose and face, but no signs of general irritation. 



The feeding was continued until the end of June, but although the 

 Lincoln showed evidence of irritation by biting at its body and rubbing 

 against solid objects, and the Merino by the marked reddening of the skin, 

 no acute symptoms, such as are seen in the field, were evinced. During the 

 whole of this period, however, there was comparatively little daily sunshine, 

 and the weather was cold. Furthermore, the plants were old, and it was 

 difficult to get the animals to eat them, even after starvation. It was there- 

 fore decided to discontinue the experiments until the following spring, when 

 the plants would be young and succulent, and there would be more sunny days. 



On 1st October, 1919, feeding experinients were recommenced. The 

 plants were green and succulent, but had not begun to flower. The animals 

 ate them quite readily, but no symptoms of irritation were shown until the 

 thirteenth day, prior to which, however, the weather had generally been dull 

 and overcast. Subsequent to this, owing to the Merino being wanted for 

 another experiment, the feeding was confined to the Lincoln. On 13th 

 C)ctober a consignment of the plant, which had commenced to flower, was 

 received. 



On the thirteenth day from the recommencement of feeding the animal 

 was observed rubbing itself against posts, &c., and on the outside of each 

 leg (on the forelegs just above the knee, and on the hind legs just above 

 the hock) i-aw excoriated areas about 2 inches in diameter were noticed, 

 the wool having been torn out as if by biting. Areas in the region of the 

 axillae and the flanks no*; covered by wool were distinctly reddened, and on 

 the sides of the chest near the elbow there were a number of papules and 

 some exudate of dried plasma. The irritation, or rather the sensitisation, 

 appeared to be general, as the animal showed signs of gratification on being 

 lubbed along the back, loins, &c. The following seven or eight days were 

 cloudy and comparatively sunless, although hot. During this period the 

 symptoms abated, and the raw surfaces scabbed o\er. On the twenty-third 

 day and onward sunny weather became the rule, and symptoms gradually 

 became more pronounced, until finally a typical picture such as is observed_ 

 in the field was produced. 



' The condition became acute about three weeks after the beginning of 

 feeding, and then gradually increased in intensity, until at times the 

 irritation and Biental depression appeared very pronounced. During dull 

 days symptoms would disappear, only to reappear in all their intensity when 

 the sun shone again. There was considerable abatement, if not entire 

 absence, of skin irritation at night, as was shown by the fact that the raw 

 surfaces would scab over during that period, only to be rubbed or gnawed 

 afresh during the day. At daytime, considerable uneasiness was evinced by ■ 

 the animal scraping on the floor with its hoofs, frequently lying down and 

 rising again soon afterwards, or wandering around the pen. At other times 

 mental depression was the most pronounced feature, the animal standing 

 with its head pressed against the bottom of the wall of the pen, and refusing 



