478 mr j. heebert parsons. 



Methods, 



Experime7ital and Chemical. 



Experimental. — The experiments were performed upon fox- 

 terrier bitches, whose body-weight varied from 4*5 kilos to 

 11 kilos. 



Previously to the operation the animals were kept in the 

 laboratory for about a fortnight, and during this time observa- 

 tions were made upon the nitrogenous intake and output for 

 a continuous period of a week. 



The animals were amesthetised with chloroform, a hypo- 

 dermic injection of ^ to 1 gr. of morphia being given 

 immediately after anaesthesia was complete, and the adminis- 

 tration of chloroform was continued throughout the operation. 



The operation consisted in the removal of a variable amount 

 of the thyroid gland. The skin having been shaved and 

 cleansed, a median incision was made over the trachea and 

 lower part of the larynx, and one thyroid lobe exposed. This 

 was then quickly removed, the greatest care being taken to 

 keep close to the gland, so as not to injure the recurrent 

 laryngeal and other nerves in the neighbourhood. Usually 

 either the whole or a variable amount of the opposite lobe was 

 removed either at a subsequent operation or at the same 

 sitting. When a portion of the gland was removed, it was 

 usually the lower part of the lobe, so that one parathyroid 

 at least was left intact. Bleeding from the cut surface of the 

 gland was easily controlled by pressure for a short time with 

 aseptic wool. 



Full antiseptic precautions were employed. All the wounds 

 healed by first intention, under a dressing of antiseptic wool, 

 fixed in place by collodion. The animals were usually perfectly 

 well an hour or so after the operation. 



The portion of lobe removed was weighed and also the 

 opposite lobe, and thus a rough estimate of the amount of 

 tissue left was determined. 



Chemical. — The mode of procedure was exactly the same as 

 that employed by Dr J. Eose Bradford (12) in his experiments 

 upon the metabolism after partial extirpation of kidney. 



