16(5 GYPSY AM) BROWX-TAIL MOTHS. [Jan. 



As the amount of inoculalde material at hand was small, but few 

 animal inoculations were performed. Mice were inoculated subcutane- 

 ously and intraperitoneally with both active nettling hairs and nettling 

 hairs inactivated by soaking in a dilute solution of an alkali. The net- 

 tling hairs were made ] 'radically sterile by boiling for ten minutes in 

 strong alcohol, a process which does not destroy their specific action, 

 - and then suspended in a .6 per cent, solution o'f sodium chloride. 

 Probably on account of the tendency of the fresh, active nettling hairs 

 to rise to the surface of the suspension fluid, only a small number were 

 injected, for they were found with difficulty in the tissue. The inacti- 

 vated nettling hairs, on the other hand, were evenly distributed in the 

 suspension, and were found in the tissue in large numbers. Some of 

 the mice, more especially those receiving the active nettling hairs, showed 

 evidence of intense itching of the skin at the site of inoculation. Fifteen 

 hours after the inoculation, a slight subcutaneous swelling, more marked 

 in certain of the mice which had been inoculated with active nettling 

 hairs, was distinguishable. 



A mouse killed twenty-four hours after inoculation with active net- 

 tling hairs showed an ill-defined, pinkish-tinged area of subcutaneous 

 edema at the site of injection. Stained sections of this area show skin 

 as well as subcutaneous tissue distended with fluid exudate. La rue 

 numbers of polynuclear leucocytes are present, scattered through the 

 tissue. No nettling hairs are present in that portion of the lesion from 

 which the sections are taken. The peritoneum presented no gross lesion. 

 Stained preparations of the mesentery show numerous minute inflam- 

 matory foci, consisting of aggregations of phagocj'tic cells, intermingled 

 with lymphoid cells. There is also a small number of polynuclear leuco- 

 cytes scattered through the mesentery. The nettling hairs are often 

 apparent within these foci of inflammation. 



A mouse killed twenty-four hours after inoculation with the inacti- 

 vated nettling hairs presented a small, well-defined, dull reddish area 

 on the inner aspect of the skin at the site of inoculation. Sections of 

 this lesion show enormous numbers of nettling hairs imbedded at about 

 the level of the superficial muscle layer, the fibers of which are here 

 either degenerating or necrotic. Some fibers are actually pierced by the 

 haii-s. In the iiiuiH'di.-iie vicinity of the injury are lame numbers of 

 polynuclear leucocytes, many of which are disintegrated. There is prac- 

 tically n<> distension of the surrounding tissue with fluid. On the peri- 

 toneum of this mouse were several minute whitish flecks, apparent to 

 the naked eye. The histological study of the mesentery and mnentum 

 reveals very numerous foci of inflammation of the same general charac- 

 ter as those found in the mouse inoculated with the active net Him.: hairs. 

 These inflammatory areas consist chiefly of collections of pha^ncytic 

 cells grouped about the nettling hairs. Lymphoid cells are not so numer- 

 oii-: as iu the legions of the mesentery in the preceding case. 



In mice killed foi-ty-ei-.-lit hours after the inoculation the subcutane- 

 ous lesions were scarcely distinguishable, and. on account of the dilli- 



