418 GEOEGE H. HOXIE 



infants because of the abnormally broad shadow of the upper mediasti- 

 num. 



"Furthermore, the superior opening of the thorax in a young child 

 measures only 2 cm. in diameter, and it is in this so-called critical space of 

 Grawitz that pressure occurs. A thymus could, therefore, be compara- 

 tively small, that is, less than 2 cm. in thickness, and still might compress 

 the trachea, esophagus, blood vessels, etc., which pass through the superior 

 opening of the thorax. " 



Friedlander also points out the necessity of using a soft tube, of mak- 

 ing an exactly symmetrical exposure, and of focusing on the submanubrial 

 space. 



Treatment of Enlarged Thymus 



If now we assume the position that the livperplasia of the thymus is 

 secondary or compensatory to other constitutional conditions, our therapy 

 will be directed chiefly towards the condition of the other organs of the 

 body, and attack the thymus only when its size threatens trouble. In chil- 

 dren, however, it is this very matter of size that causes much of the trou- 

 ble. Therefore, with them we seek first of all its reduction. 



The thymus seems very sensitive to the X-ray, and, therefore, in cases 

 of hyperplasia exposure to the X-ray or radium is the method of choice. 



Cook quotes with approval Lange's conclusions, as follows: 



a l. Roiitgen irradiation of the thymus produces artificial in- 

 volution of the gland. 



2. X-ray therapy is the method of choice in cases of enlarged 

 thymus in children, whether the symptoms be. mild or urgent. 



3. Urgent cases should receive repeated massive doses. 



4. Recurrence due to regeneration of the gland is to be 

 watched for and controlled by further treatment. 



5. Children whose physical or mental development is retarded 

 should, if suspicion is directed towards the thymus, receive tenta- 

 tive X-ray treatment, even though a positive diagnosis cannot be 

 established. 



6. X-ray therapy as a precautionary measure, or pre-operative 

 treatment, may enable children of the so-called lymphatic type to 

 withstand intercurrent disease or anesthetics, which would other- 

 wise prove fatal. 



7. Pre-operative exposure of older children and adults, where 

 there is a suspicion of enlarged thymus, might lessen operative 

 mortality. 



(S. Routine pre-operative X-ray treatment in cases of hyperthy- 

 roidism should be resorted to with a view to lessening operative 

 mortal itv. 



