THE CHICKEN-SCAB. 63 



THE CHICKEN-SCAB. 



{Sarcojjtes r/mfans Roh. or Kneinldohyptes 'vhviparus Fuerst.). 



This mite selects such portions of the skin as are free 

 from feathers, and causes a pecuHar itch upon the 

 legs of the bird (fig. 35), sometimes extending to the 

 head (fig. 36), where it forms discolored spots. The 

 mites possibly reach the combs of chickens when the latter 

 are scratching these organs, or when they peck at the itch- 

 ing legs. Combs invaded by this mite sho-w white dots and 

 lines covered by minute scales, which rub off quite readily; 

 below them the skin is brownish, contrasting strongly with 

 the normal red color. Later the feathers 

 on the head undergo a peculiar change; 

 they turn whitish, lose their glossy ap- 

 pearance, and stand on end. Infested 

 legs are distinguished by greyish-white 

 spots or scabsof various shapes and 

 sizes, and by brownish swellings in the 

 skin, and in extreme cases by a greatly 

 swollen and scabby appearance. Under 

 these scales we see a yellowish substance 

 Fig. 34. Scab-mite of chick- in which are the numerous burrows of 



en. female. Greatly en- .1 • , aiai 1^1 r- 1 • 



larged. Original. the mitcs. 1 he scabs thus formed give 



the legs a very peculiar and unsightly appearance — they 

 look "chalky." 



All the actions of the fowls show that considerable itch- 

 ing takes place, which, however, does not as a general rule 

 destroy the appetite of the patients. The young and six- 

 legged mites are fairly active, and one diseased fowl will 

 soon scatter the infection to all other birds living in the 

 same roost. 



If we investigate, by means of a microscope, a small 

 piece of the scab caused by these parasites, we find in most 

 of the burrows small and yoimg mites, and in the blind end of 

 the burrow large females and males. But we do not find eggs in 

 such burrows, as we do in the case of other itch-mites. Prof. 

 Fuerstenberg discovered that these mites produced living 

 young, and therefore changed the former name of these 



