[CAMERON] EFFECT ON RATS OF THYROID FEEDING 59 



day of treatment in a typical tetany posture. At autopsy rat 4 was found to be a 

 male. The testes were high up and very small, and the animal was in poor con- 

 dition. None of the rats showed marked fat-deposits. All thyroids were bright 

 red in colour. 



Experiment 3. A litter of 7 rats, 4 males and 3 females, born September 14th. 

 Two males and one female were used as controls. Thyroid feeding (1:5000; pre- 

 paration A) was commenced on the 30th day of age, and continued 18 days; sub- 

 sequent normal feeding was given for 48 days. Rat 4 was found dead on the morning 

 of the 15th day of treatment in a typical tetany position. On the afternoon of the 

 13th day of treatment rat 7 developed typical tetany, with rapid heart beat and 

 respiration, dragging of hind limbs, and tremors. This attack gradually passed 

 off, and the animal had apparently completely recovered 3 hours later. It had no 

 subsequent attacks. At autopsy all animals showed fat-deposits, and all thyroids 

 were bright red in colour. 



Experiment 4. A litter of 7 rats, 4 males and 3 females, born December 8th, 



1921. Two males and one female were used as controls. Thyroid feeding (1:5000; 

 preparation B) was commenced on the 33rd day and lasted 19 days. Subsequent 

 normal feeding lasted 37 days. At autopsy rat 4 (thyroid-fed) was distinctly fatter 

 than the others. All thyroids were bright red. 



Experiment 5. A litter of 7 rats, 3 males and 4 females, born December 25th. 

 One male and 2 females were used as controls. Thyroid feeding (1:2000; prepara- 

 tion B) was commenced on the 30th day of age, and lasted 18 days. Subsequent 

 normal feeding lasted 37 days. All thyroids were bright red at autopsy. 



Experiment 6. A litter of 10 rats (another died before the experiment com- 

 menced) small and somewhat weak, 3 males and 7 females, born February 11th, 



1922. Thyroid feeding (1:5000; preparation B) commenced on the 32nd day of 

 age and lasted 19 days. Subsequent normal feeding lasted 18 days. 



Rat 2, a control animal, was found dead on the morning of the 54th day. This 

 animal was less than half normal weight. 



Rat 4 commenced to develop tetany at 9.00 p.m. on the 7th day of treatment. 

 Apparently no bread and milk had been eaten during the evening. At 9.55 p.m. 

 the tetany was distinct, the animal moved clumsily, with hind limbs extended; 

 heart beat and respiration were violent. It was tapped gently; this was followed 

 by spasmodic jerking back of the head, and subsequent convulsions, in which the 

 animal lying prone suddenly bounded in the air, while there were typical tetanic 

 movements. The movements changed in type to spasmodic elevation of the hind 

 limbs. The eyes gradually glazed. At 10.02 the animal was extended, with slow 

 and deep respiration; it showed occasional spasmodic jerks. At 10.05 the breathing 

 was still slower — irregular gasps. At 10.09 each respiration set up a wave-spasm 

 which passed down from the fore-limbs (greater extension) to the hind-limbs (which 

 were raised). One minute later the animal was dead in the typical tetanic position. 



Rat 6 was found dead on the morning of the 7th day of treatment. Tetany was 

 suspected. 



Rat 7 showed onset of tetany at 5.30 p.m. on the 7th day of treatment; the 

 heart beat was rapid and the fore-legs flexed. At 7.00 the symptoms were more 

 marked, both heart-beat and respiration were more rapid than normal and the 

 hind limbs were extended. At 9.00 the animal was distinctly better and feeding. 

 There was apparently no attack on the 8th day, but a slight attack was noticed 



