THE SCAB-MITE. 231 



gin, as well as the product of contagion ; and the acarus, having 

 sprung into life within the pores of the skin, obeys the laws of all 

 living beings as to its after existence and multiplication." 



It shows with what caution speculations should be indulged in, 

 and how much safer it is to say " we do not know," than to haz- 

 ard explanations which may be wide of the truth and misleading. 

 It has long been known that the origin of the existence of all ani- 

 mal life is an egg produced and fecundated by parents, and the 

 scab-mite being no exception to this law, comes forth from an egg 

 and springs into life just as a chicken does. In both cases the egg 

 is deposited and hatched, and produces the mature animal. The 

 female scab insect, seen at figure 88, is larger than the male, 

 which is shown at figure 89, magnified 

 2,500 tunes. One male suffices for many 

 females, and is longer lived than the 

 female. The latter dies after producing 

 her eggs, which she deposits in the pores 

 of the skin, or in the furrows of the scab 

 which she has helped to produce. Her 

 eggs are numerous, and being hatched in 

 three days, her progeny increase rapidly. 

 One female acarus can produce a million 

 and a half of progeny in 90 days. This 

 facility of increase explains the rapidity Fig. 89. MALE SCAB 

 with which the disease spreads through a 



flock, and proves the necessity for instant and energetic remedies 

 or effective preventives. 



The symptoms first observed are restlessness and uneasiness, and 

 the observant shepherd will have his suspicions aroused and search 

 for the cause on the first appearance of these symptoms amongst 

 his flock. As the disease progresses, the sheep are found rubbing 

 or scratching themselves, or biting or nibbling amongst their 

 wool. The attention should then be directed to the parts rubbed 

 or bitten. If scab is present, the skin will be at first white in 

 color and of a thicker texture than the rest, and moist or covered 

 with a yellow exudation. Later these parts are covered with scab 

 and the wool falls off or becomes loose. If a lock of this wool be 

 laid upon a sheet of white paper, the mites will be seen with the 

 unaided eye, as they crawl from it. If the disease is neglected, 

 the scabby spots enlarge and increase in number, the wool appears 

 ragged all over, and falls off in patches. Upon these bare spots 

 dense brown or yellow scales are seen, and if the sheep can reach 

 a fence or a post, the scabs are rubbed until they bleed and be- 



