The above table does not include the 123 non-reacting cattle in which no tuberculosis lesions were found. XX The autopsy totals of cattle tested intradermally with 10 per cent Koch's Old Tuberculin or 5 to 10 per cent alcoholic precipitated. tuberculin are: Number of reacting cattle in which tuberculous lesions were found Number of reacting cattle in which no tuberculous lesions were found 5.5 Total for reacting cattle 73 100.0 Number of non-reacting cattle in which no tuberculous lesions were found Number of non-reacting cattle in which tuberculous lesions were found Total for non-reacting cattle 129 100.0 THE LOCAL REACTION TO THE INTRADERMAL INJECTION IN CATTLE A positive intradermal reaction is indicated by a thickening of the subcaudal fold or by the appearance at the point of injection of a characteristic sensitive swelling varying in size from that of a small pea to that of an orange. The swelling may be either soft and oedematous or hard and inflamed. A recognizable reaction may be present on the sixth hour, but generally the reaction is first clear about the twelfth hour and continues to increase in size until the forty-eighth hour. In some instances we have observed that the early local reactions disappear before the forty-eighth hour, while in others delayed reactions have been noted which did not appear until the nineteenth hour. In order to be certain of every case, observations must be taken at least twice, preferably about the thirty-sixth and seventy-second hours. If only one observation can be made it should be on the seventy-second hour. Small indurations at the point of inoculation about the size of the head of a parlor match frequently occur in normal non-reacting cattle, but anything larger than this which persists to the seventy-second hour should be considered a positive reaction. In recording the reactions, a convenient method for comparison is to describe the size of the swelling as pea size, hazelnut, walnut or hen's egg size. The exact size, if desired, may be measured by means of calipers such as are shown in plate 1, figure 3. Romer and Joseph43 consider that a thickening of the skin fold more than three millimeters larger than the thickness previous to injection should be considered a positive reaction. Cases in which the increase in thickness only amounts to three millimeters, they consider doubtful and subject to a retest. In our work, however, we have found the measurement of the swelling was not of much assistance. Experience and practice will enable the operator to judge of the size of the swellings without measuring, although for the sake of accurate records we have made a practice of taking careful measurements. In judging a local swelling, the observer should depend more upon the shape, appearance, tenseness, sensitiveness and location with respect to the exact point of injection, than upon the actual measurements. Only experience can teach an operator how to be certain of a positive reaction when the local swelling is small. This is especially true when tuberculin containing glycerin has been used. THE THERMAL REACTION TO THE INTRADERMAL INJECTION IN CATTLE Moussu and Mantoux37 state that no thermal reaction follows their method of performing the test. On the contrary, we have found that tuberculous cattle usually do show a marked temperature reaction when injected intradermally with the dosage and strength of tuberculin recommended by these investigators. Moussu and Mantoux used tuberculin brut (Koch's old tuberculin) diluted with ten volumes of physiological salt solution. Their dose was from 10 to 15 cc. We have used this kind of tuberculin in testing 207 cattle when frequent temperature readings were taken after the intradermal injection. One hundred and twenty-four showed a local reaction swelling. In 101 of these 124 cases distinct temperature reactions also occurred. Three cows which showed a local, but no thermal reaction. were autopsied and found to be tuberculous. These cases are described in detail later. The following table of twenty tests selected at random from the 101 cases mentioned above, shows the typical height of the thermal reaction to Moussu and Mantoux's method. 106.6 105.0 103.1 101.0 TABLE 4 TYPICAL CASES SELECTED TO SHOW THAT CATTLE REACT THERMALLY TO THE INTRADERMAL TEST. INTRADERMAL TEST RECORD Ear Date: May 20, 1913 31 Min Max. 6 hr. 9 hr. 12 hr. 14 hr. 16 hr. 18 hr. 20 hr. Test Result Before TEMPERATURES SUBCUTANEOUS TEST RECORD After Injection Min. Max. 8 hr. 10 hr. 12 hr. 14 hr. 16 hr. 18 hr. 20 hr. 101.7 + Test Result 46 100.6 101.0 101.8 101.4 104.2 103.6 103.2 100.0 100.7 48 101.4 101.8 102.4 102.7 104.8 56 101.2 101.8 103.2 106.3 105.6 101.4 +40 mm., orange, 104.0 103.6 102.9 100.6 104.8 104.4 102.8 105.0 106.2 105.0 104.5 102.4 101.8 85 100.6 101.4 104.0 105.5 105.6 104.6 103.8 103.1 102.8 106.0 104.6 104.0 102.5 101.6 101.4 105.6 105.6 104.0 100.6 99.9 99 100.6 101.1 103.1 104.8 107.9 105.4 104.2 101.2 100.0 103 101.8 102.5 103.1 103.8 106.6 106.2 105.8 105.4 100.1 113 101.3 102.0 102.5 103.2 105.4 105.1 103.6 102.4 102.0 114 100.2 104.4 104.2 102.4 102.6 102.6 102.0 101.7 All animals in this table reacted to both tests. +20 mm., walnut medium 13 mm., hazelnut medium +20 mm., walnut medium +15 mm., walnut, medium 1 100.8 101.7 106.1 106.2 104.0 103.0 102.3 102.0 99.8 101.4 104.2 105.6 105.4 104.6 104.6 104.0 104.4 100.4 102.8 102.2 104.0 106.0 106.0 105.8 105.2 104.0 101.2 101.4 102.6 104.6 105.9 103.7 102.1 102.2 100.6 103.0 105.0 104.4 102.4 101.8 101.0 99.8 |