xiv THE LYMPH 543 



tired after a few steps; they can hardly drag a weight much 

 lighter than that drawn easily by normal puppies. The difference 

 is very marked even two months after the operation ; it then 

 diminishes, and finally disappears. In the first two months after 

 the operation these puppies easily fall ill and die without any 

 particular cause. Nothing abnormal can be detected at the post- 

 mortem, except that the gastro-intestinal mucosa is congested. 



The effects of extirpating the thymus in chicks 4 to 5 days old 

 are more apparent. Immediately after the operation they exhibit 

 only the effects of operative traumatism, which soon passes off, so 

 that nothing abnormal is seen the next day. Three to four days 

 after the operation, however, motor disturbances appear, and go on 

 increasing : weakness of limbs, uncertain gait, slight tremors of all 

 the muscles, finally torpor, followed shortly after by death. In 18 

 operated chicks, 15 died with these symptoms 7 to 8 days after 

 the operation ; 2, in which the disturbances were less pronounced, 

 recovered after 10 to 12 days; one only succumbed during the 

 operation. 



Of 6 chicks, deprived of the thymus on one side only, one 

 alone (operated on 2 days after birth) perished, the symptoms 

 resembling those of chicks in which both sides were operated on : 

 the others survived, merely exhibiting a slight weakness in the 

 first days after the operation. 



In chicks of 10 to 25 days the excision of the thymus, either on 

 one side or on both, produced no perceptible effect. 



In the interval between the first and second publications of 

 Tarulli and Lo Monaco, two French experimenters, Abelous and 

 Billard (1896), published their work on the effect of thymus 

 extirpation in the frog, which (as might be anticipated) is more 

 marked than in the case of birds, the thymus in amphibia being a 

 permanent organ, functioning throughout life. 



One to two days after the bilateral excision of the thymus, the 

 frog exhibits serious motor disturbances, as shown in progressive 

 muscular debility and incapacity for work, which increases till it 

 amounts to paresis, paralysis, and the death of the animal. It is 

 remarkable that while neuro-muscular activity becomes exhausted, 

 sensibility remains intact, and even increases at first. 



Some hours after the operation the copper-green colour of the 

 frog (Rana esculenta) changes to a yellowish hue, and the area of 

 black spots is contracted ; only the head and limbs escape this 

 discoloration. On the following day this phenomenon is less 

 pronounced ; with the onset of the muscular weakness it reappears, 

 and increases steadily till death. Along with the discoloration 

 dystrophic effects begin to appear on the skin in the form of 

 ulcers, zones of necrotic destruction, and subaponeurofcic ecchymoses. 

 These changes become more serious the longer the animal survives. 

 The ulcerated surfaces are highly hyperaemic, and bleed at the 



