176 OPERATIVE TECHNIQUE. 



4. Parench}matOLis injection consists in introducing solutions of 

 drugs into the parenchyma of organs, like the thyroid or lymphatic 

 glands, or into muscles or pathological new growths. The active 

 agents are thus brought into immediate contact with the affected 

 tissues. In veterinary surgery actinomycotic growths are the 

 commonest objects of such treatment, though tumours and the 

 swellings of goitre have also been injected, but with var}'ing results. 



Solutions of acetic, carbolic, or lactic acids, iodine, zinc chloride, 

 papain, etc., have all been used for parenchymatous injection. In the 

 hands of several operators iodine and papain have given good results 

 when employed against soft new growths and goitre. 



A rather stout needle is inserted — if possible, into the centre of the 

 organ or growth (sometimes a specially long needle is required), and 

 the solution injected. A few drops are often sufficient. Slight pressure 

 should be kept on the piston during withdrawal. Sometimes several 

 injections are made at different points. The operator judges of the 

 need for repeating the operation by the condition of the diseased 

 parts, and by the reaction which follows. As a rule one should wait 

 until all signs of the previous treatment have disappeared. 



The principle of parenchj-matous injection is not new, for a some- 

 what similar process, viz. the introduction of solid caustics like arsenic 

 and sublimate, has been in use since very early times. 



