178 PARENCHYMATOUS INJECTIONS — CASTRATION. 



recommends subnitrate of bismuth or 1 per cent, iodine solution 

 (Lugol's solution) repeated every few days. 



(d) Parenchymatous 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 varying 

 results. 



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

 strychnine, nuclein, 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. Some- 

 times 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 until all signs of the previous treatment have 

 disappeared. 



The principle of parenchymatous injection is not new, for a 

 somewhat similar process, viz., the introduction of solid caustics, 

 like arsenic and sublimate, has been in use since very early 

 times. 



XV.— CASTRATION. 



For economic reasons, the removal of the testicles or ovaries, 

 or the destruction of their functions, often becomes necessary. The 

 gelding is, for most purposes, more useful than the stallion ; its 

 conformation is modified, it is usually more tractable, and it can 

 be worked in company with mares, a proceeding which is seldom 

 safe in the case of stallions. The flesh of pigs and birds becomes 

 more palatable, and animals fatten more readily after castration. 

 Sheep fatten more quickly, and their wool becomes finer and more 

 abundant. The milking period is prolonged in the castrated cow, 

 and the danger of unsuitable animals breeding is removed. Dogs 



