THE MILK TEETH. 495 



three permanent molars on each side are cut, like the milk teeth, 

 directly through the gums. 



The cutting of the milk teeth, is doubtless, in many cases, though 

 not necessarily, a painful process; it may even produce reflex nervous 

 irritation, which may affect the digestive, circulatory, or muscular sys- 

 tems, causing diarrhoea, fever, convulsions, or paralysis. Lancing the 



Fig. 86. 



I 



Pig. 86. Left side of lower jaw, at the age of five years, having the bony substance partly removed, to 

 show the second set of teeth, forming beneath the temporary or milk teeth, i. temporary incisors, c, tem- 

 porary canine, wi, first and second milk molar, and first permanent molar, i', permanent incisors, form- 

 ing in recesses or sacs within the jaw, below the milk incisors, c', permanent canine, b', permanent 

 bicuspids, commencing below the two milk molars, which they replace, m', second permanent molar, rising 

 behind the first, which is already through the gum. Above and behind thia, is the sac of the wisdom tooth, 

 or third permanent molar. 



gums of children, affords relief in two ways: it removes the tension of 

 the inflamed gums, and also leads to the formation of a yielding and 

 easily absorbed cicatrix, in place of the firmer tissue of the gums. The 

 cutting of the ten anterior permanent teeth, is unattended by pain, 

 for the crown of each, passes through an opening in the gum, left by 

 the shedding of a milk tooth; but the cutting of the permanent molar 

 teeth, which have no precursory temporary teeth, is usually a painful 

 process, more particularly the cutting of the wisdom teeth, the jaw 

 and gums being frequently so cramped, that the tooth has not sufficient 

 room to rise. 



At about the age of five years, immediately before the shedding of 

 any of the milk teeth, the jaw-bone contains more teeth than at any 

 other period of life ; for, besides the milk teeth, all the permanent 

 ones, except the wisdom teeth, are found in an advanced stage of 

 growth embedded in the bone (see Fig. 86, and description). The 

 rudiments of the wisdom teeth first appear about the sixth year. The 

 order and date of the eruption of the permanent teeth, in the lower 

 jaw, are expressed in years, in the annexed diagram ; the correspond- 

 ing teeth in the upper jaw appear usually, in each case, somewhat 

 later. 



