266 The Philippine Journal of Science 192s 



From a fifth case a dry, apparently regressing or stationary 

 lesion of four or five months' duration was removed before 

 treatment, and another similar nodule three days after an in- 

 jection of neosalvarsan. 



Sections of nodules from each case, measuring 1 millimeter in 

 thickness, were immediately placed in Zenker's fluid and in 10 

 per cent formalin. The Zenker-fixed material was embedded in 

 paraffine and stained with hematoxylin and eosin. The forma- 

 lin-fixed tissue was stained by Levaditi's silver method. (5) 

 CASE 1 



Primary yaw appeared on the ankle four months previously, 

 followed in one month by a crop of secondary papules over the 

 entire body, accompanied by occasional attacks of fever, chills, 

 and pain in the bones. Many of the lesions increased in size 

 until at present they measure from 0.5 to 1 centimeter in diame- 

 ter. They are discrete, elevated, rounded or oval nodules, the 

 surface fungating and covered by an opaque, yellow, moist crust. 



Yaw 1. — October 8. Such a yaw on the chest, measuring 0.8 

 centimeter in diameter, was excised by Doctor Franco under 

 local anaesthesia. On cut section it showed a firm, grayish yel- 

 low, thickened epidermis containing a few minute haemorrhages, 

 evidently in an acute stage of inflammation. Pieces of tissue 

 were fixed immediately in 10 per cent formalin and in Zenker's 

 fluid. 



Microscopically there is an acute inflammation of the skin, 

 with an enormous exudate of leucocytes in the thickened epi- 

 dermis and a serous, in places haemorrhagic, exudate in the 

 elongated papillae of the corium. The acute inflammatory 

 changes in the corium are confined almost entirely to the 

 lengthened and swollen papillae and to a thin zone just beneath 

 the basal layer of epithelium elsewhere. The reaction is char- 

 acterized especially by an exudation of serum which spreads 

 apart collagen fibrils and fills up the spaces between them. To 

 a less extent leucocytes and red cells are present in this peri- 

 vascular tissue; in places fibrin is deposited and small haemor- 

 rhages have occurred. 



Corresponding to the elongation of papillae the total width 

 of the epidermis is about fifteen times the normal, and most of 

 this increase in volume is due to the accumulation of leucocytic 

 and serous exudate within this layer. Foci of leucocytes occur 

 in the form of miliary abscesses which are numerous and sit- 

 uated most characteristically in a midzone somewhat nearer the 



