VACCINE-THERAPY 181 



fully passed off no reaction is likely to follow a second injec- 

 tion. This fact is sometimes made use of by unscrupulous 

 sellers, who inject their own animals previous to expert 

 examination and injection. This in itself is a strong plea 

 for the limited sale of tuberculin, and its use restricted 

 to the hands of recognized experts.* 



The Ophthalmic Test. — Calmette noticed that a few 

 drops of tuberculin applied to the conjunctiva of a man 

 suffering from tuberculosis was productive of conjuncti- 

 vitis, and Vallee showed that the same condition took place 

 in animals. 



A few drops of tuberculin are placed in the conjunc- 

 tival sac by means of a sterile glass pipette — that 

 used for opsonic work will answer the purpose — and the 

 eyelids closed and gently moved about. When a reaction 

 takes place, the membrana nictitans becomes very red and 

 its border thickens ; the other eye in itself acts as a useful 

 standard by which to estimate the degree of reaction taking 

 place in the tested eye. The reaction sets in earlier than by 

 the subcutaneous method, from six to nine hours, and from 

 twelve to twenty-four hours a purulent secretion forms on 

 the inner canthus, which appears as a long, purulent mass 

 drying into a crust, and finally falling off. 



Where one gets a slight conjunctivitis followed by a 

 watery or even a mucous flow, these are of no diagnostic 

 value ; the discharge must be purulent. A prior injec- 

 tion of tuberculin has no effect upon the reaction in the 

 ophthalmic test. This should prove useful in those cases 

 of unscrupulous tampering, and also in those animals where 

 the temperature is too high to use the subcutaneous test. 



Tfie Cutaneous Test. — Pirquet showed that on inoculating 

 a small quantity of tuberculin into the upper cuticle layers 

 of a tubercular person, a local reddening and swelling took 

 place, and Yallee demonstrated that a similar process took 



* If, however, from force of circumstances such a long time cannot 

 be allowed, a reaction may be obtained if 3 to 5 c.c. or more of 

 tuberculin is given. 



