7 
eaten by stock, but there seems to be some evidence in support of the con- 
tention of the Oudtshoorn farmers that at times it may be harmful. Some 
farmers will certainly not allow their horses to eat the Malva.* The whole 
subject is of much interest, and may become of importance should the 
defects recur from time to time; undoubtedly we have some poisonous weed 
which is capable of influencing the blood-pressure of a bird to such a degree 
that the barbules do not form on the growing feathers. A careful study 
on the spot would probably reveal the cause, and an investigation should 
be undertaken if the trouble breaks out again. At the present stage we 
can only explain how the trouble has been produced without knowing: the 
cause. 
CoMPARISON OF THE Oup?TsSHOORN DEFECTS WITH THE ORDINARY 
SHRINKAGE Bar. 
One is naturally inclined to compare this new defect with the ordinary 
shrinkage bar with which the ostrich farmers everywhere are familiar. In 
the last number of the Agricultural Journal a full account was given of 
how the shrinkage bar is produced, namely, by the wrinkling of the feather- 
sheath upon the soft growing feather at the region of the weaker night rings. 
In the shrinkage bar the defect is always very narrow, being only the 
width of a night ring, that is, about a sixteenth of an inch; moreover, the 
shaft and barbs are often indented by the wrinkling, while the barbules 
are usually present, but not properly separated from the barbs. In this 
Oudtshoorn trouble the barbules have either not been formed or are very 
rudimentary, there is no kinking of the barbs and shaft, and the defect is 
continuous for both the day and night growth, having certainly lasted over 
a week in the case of the first and second attacks, though shorter in the 
third. It points to some continuous ailment in the bird as a whole. While 
primarily the shrinkage bar is due to the differences in blood-pressure, it 
is only the difference between the day and night periods which has to be 
taken into account; in this newer defect also we have a diminished blood- 
pressure to deal with, but it is continuous, irrespective of the day and 
night changes. The physiological causes of the two defects are therefore 
altogether different. The one is much rarer and should be easy of remedy 
if, whenever it appears, an examination is made of the weeds the bird is 
feeding upon, while the other is more constitutional and dependent upon 
the general condition of the bird influenced by climatic and other changes. 
How Dense Heavy Fives are PRopUCcED. 
From Fig. 2 and the facts presented in connection therewith we are 
now in a better position to understand the physiological conditions under 
which a dense heavy flue is produced. A feather is very largely dense in 
proportion to the length of the barbules. Probably more than in any 
other way the present wave of feather improvement shows itself in an in- 
crease in the length of the barbule, though associated with it is an increase 
in width and length of the flue and a closer arrangement of the barbs on 
the shaft. In these improved feathers much depends upon the strain of the 
* The introduction of the question of the poisonous nature or otherwise of the Kissie 
Blaar (walra parviflora) before a recent meeting of the Upper Albany Farmers’ Association 
brought forth expression< of opinion very divergent in their nature, some contending that 
the plant was perfectly harmless while others were just as convinced by their experience 
that it was poisonous. As soon as opportunity offers it is hoped to conduct experiments on 
the subject. It seems not unlikely that different plants may be included under the name 
Kissie Blaar, and in any discussion on the subject it is desirable that specimens of the plant 
should be forwarded to Dr. 8. Schonland, Albany Museum, Grahamstown, who has kindly 
offered to identify them. 
