2l8 MEDICAL BACTERIOLOGY 



Von Pirquet Test. For this test a mixture of Koch's tuberculin i part, 5 

 per cent, aqueous solution phenol i part, and normal salt solution i part is used. 



The patient's arm is cleansed with ether and three areas about J^ inch in 

 diameter are scarified. Two drops of tuberculin are placed upon two of these 

 areas and allowed to dry in, care is taken that no tuberculin touches the third, 

 the control area. 



The scarified areas must be at least 2 inches apart and the degree of scarifica- 

 tion must be exactly the same in each instance. Only the epiderm is scarified, 

 blood must not be drawn. A positive reaction shows redness and edema of the 

 areas inoculated with tuberculin 48 hours after introduction, a papule or vesicle 

 follows and subsides in about a week. The control area shows none of these 

 changes. 



The results of the work of the last couple of years suggest that in the near 

 future the intracutaneous tuberculin test as carried out by Craig of London, 

 Canada, will supplant the Von Pirquet. This is substantially as follows: 



The patient's arm is cleansed as for a Von Pirquet. A drop of sterile glycerin 

 broth is placed on the skin and driven in by puncturing the epidermis six times 

 with a round, solid, sewing needle. Several inches away a drop of tuberculin 

 is placed on the skin and punctures are made through this. Excess broth and 

 excess tuberculin are wiped away. In making the punctures, care is taken to 

 thrust the needle point into but not through the skin, and blood should not be 

 drawn. 



Moro Test. A 50 per cent, lanolin ointment of old tuberculin is rubbed into 

 the skin of the abdomen over an area of about 6 square centimeters. A positive 

 reaction shows a red papular eruption after i or 2 days. 



Both the Von Pirquet and Moro test have their greatest value when applied 

 to young children. A large number of apparently healthy adults show positive 

 reactions when subjected to these tests. 



Calmette's Ophthalmo Test. Calmette's ophthalmo test is performed by 

 dropping into one eye i minim of a i per cent, aqueous solution of purified tuber- 

 culin (twice precipitated with alcohol). 



This test frequently produces misleading results and is not without danger. 



RABIES (Lyssa, Hydrophobia) 



Rabies is a disease, primarily of dogs and wolves, which occurs in epizootic 

 form, in cats, cows, horses, swine, sheep, deer and various wild animals. 



In man the disease occurs as a result of infection by the bite of a rabid ani- 

 mal in the vast majority of cases dogs or wolves being the offenders. 



The bite of animals afflicted with this disease is infectious from i week before 

 they present signs of illness until the termination of the disease. 



Not all animals suspected have the disease, and fortunately, only a portion 

 of those bitten by rabid animals are infected. 



Rabies is hopeless in man, once clinical signs appear, but it is possible to 

 immunize persons infected, before the termination of the period of incubation, 



