i INTEENAL PEOTECTIVE SECEETIONS 17 



groups, however, combine and succeed each other so variously in 

 individual cases, that any separate description of them would be 

 artificial and arbitrary. 



Two to three days after the total ablation of the thyro- 

 parathyroid apparatus, the dogs begin to exhibit signs of depression, 

 and are sluggish in their movements, with a decided tendency to 

 remain crouched. They are unwilling to eat (anorexia), swallow 

 with difficulty (dysphagia), are inclined to vomit, and end by 

 absolutely refusing all food. When they try to move, or are 

 forced to stir themselves, they exhibit characteristic fibrillar 

 tremors of the muscles of the thighs, shoulders, and back. 



These symptoms gradually become aggravated and complex. 

 The animals appear uneasy, they whine (as if in pain), rub their 

 noses on the ground or wall, and shake their bodies as if they 

 itched all over. At the same time, sensibility to painful and 

 tactile stimuli seems to be objectively diminished or entirely 

 abolished, while the pressure -sense is retained (Schiff). On the 

 third or fourth day, more often on the fifth or sixth, trophic 

 disturbances make their appearance in the skin, due in great 

 measure to rubbing with diminished cutaneous sensibility. Con- 

 junctivitis and keratitis next set in, and are first catarrhal and 

 subsequently become purulent (Gley), if precautions are not taken 

 by treatment with disinfectants (Lusena). 



The muscular tremor becomes continuous ; it is complicated by 

 rigidity of the extremities, particularly the hind-limbs, in the form 

 of tonic extension ; twitches or clonic contractions of certain groups 

 of muscles, particularly in the temporal muscle and the masseters, 

 tonic contraction of the masticator muscles (lock-jaw), extending 

 sometimes to the muscles of the back and limbs (opisthotonus), 

 and assuming the form of true spasms of tetanic convulsions. 



The convulsive spasms are not infrequently complicated by 

 attacks of tachypnea of no long duration, during which there is a 

 proportionate increase of temperature (Marchesi). Sometimes the 

 tachypnea is so intense that the respirations can only be counted 

 by the graphic method (Gley). Not infrequently, at the close of 

 life, the respiratory rhythm becomes periodic (Cheyne- Stokes 

 phenomenon), but this does not last long, and is irregular in form. 



Along with tachypnea and hyperthermia there is regularly 

 tachycardia, which may reach maximal intensity (150 beats to the 

 minute). On the other hand, in the long intervals (sometimes 

 whole days) in which there are no convulsive phenomena nor 

 tachypnea, and the animal is in a drowsy, stupid state or in coma, 

 the temperature may fall gradually to two degrees below normal 

 (Ughetti), while the cardiac beats also become less frequent than 

 the normal (Lusena). Investigation of the respiratory gas ex- 

 changes agrees with this fact, as they are found to be diminished 

 after thyroidectomy (Baldoni). 



VOL. II C 



