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Appendix C.
GENERAL REMARKS ON POST-MORTEM EXAMINATIONS.
During the course of this investigation very good opportunities have been afforded us for conducting post-mortem examinations on typical cases.
In many instances, however such an examination could not be undertaken owing to the rapidity with which decomposition sets in during the hotter seasons of the year. In addition to the climatic factor, the size of the animal itself prevents the rapid radia- tion of heat, and the bulky nature of the stomachs and bowel and their contents favour the rapid growth of post-mortem micro-organisms. Indeed the changes, which set in after the death of the animal are so rapid that 3 to 4 hours after death, a satisfactory post-mortein cannot be made. Although a considerable number of animals succumbed to the disease, it was impossible to find a favourable opportunity to perform the post-mortem examination within the limit of time between death and the onset of decomposition.
The general results of the post-mortem examinations held by us were remark- ably uniform. From an external examination of the animals, the first noteworthy point is the presence of extreme emaciation. The eyes are sunken, a thick yellowish muco-purulent discharge is found around the eyes and nose. This is found agglu- tinated to the hair of the cheek. The flanks are sunken, the anus and vagina are relaxed and excoriated with the presence of a discharge similar to that found around the eyes.
Such an aggravated condition is constantly present in cases surviving 5 to 8 days. In more acutely fatal cases, these appearances are less definite, in fact, in a few cases, the external examination of the carcase may show nothing noteworthy.
Circulatory Organs.-The condition of the pericardium. It may be normal. In many instances petechiae are found in the parietal and visceral layers. They are about the size of a lentil and as a rule are most abundant in the visceral layer.
The pericardial sac occasionally contains a small amount of straw-coloured fluid. Otherwise the general appearance of the sac is normal.
The heart frequently shows small circumscribed hæmorrhagic extravasations both intra-muscular and endocardial. Otherwise the heart is to all appearance normal, although in a few instances the muscular substance is extremely soft and flabby. In one or two cases, tenacious ante-mortem clots have been found. In one case, valvular vegetations were found in the right heart. These appeared recent in origin. Their significance was not determined.
In old animals, a noteworthy point is the occurrence of marked hypertrophy of the cardiac muscle, more particularly on the left side. This condition appears to be due to the hard outdoor work done by these cattle.
Respiratory Organs.-The nares, larynx and trachea were frequently congested. Occasionally submucous hæmorrhages were found. There has never been any appearance suggestive of erosion or ulceration. The lungs may be normal, but in the majority of instances are congested. In a large number of cases interlobular emphysema was present. Cases of oedema and infraction of the lungs have been found. In two cases multiple abscesses were present. In one case, P.M. No 5, the animal had been ill for 21 days. In the other case, P.M. No. 26, the animal was sick for 12 days.
In both cases the abscesses were variable in size and shape. The smaller abscesses were about three-eighths of an inch in diamater and enclosed in dense fibrous capsules. In many cases these walls appeared to have broken down giving rise to the formation of large abscesses of very irregular outline. The pus was thick, creamy and blood stained and contained the characteristic bacillus as well as ordinary pyogenic cocci.
In no case was there ever any appearance of pleurisy, or consolidation of the lungs. The appearance of tubercular disease was also absent from every post- mortem made by us.
Cavity of Abdomen.-No excess of fluid was ever present. The peritoneum appeared to be normal with the exception of the presence of a few petechiæ. There were never signs of peritonitis. The great omentum was usually congested with a few