310 
OLOF SCHWARTZKOPFF. 
17 months are replaced 1 2 upper and lower jaw. At almost 
the same time appears the last molar, M 3, in upper and lower 
jaw. Now we have a fully developed permanent dentition, 
which is illustrated in Figure II. 
For the practical use of the swine-breeder, I will summar¬ 
ize what has been discussed above in the following 
TABULAR VIEW OF THE DENTITION OF THE PIG. 
TEETH. 
Precocious 
Pigs. 
Normal time of 
Appearance. 
Primitive Pigs. 
Milk 
Dentition. 
i 3, and c . 
i 1 . 
i 0 l u PP er jaw . 
’ ) lower jaw. 
- m 1, both. 
m 2,1 UPP^ jaw. 
’ j lower jaw. 
m3 j upper jaw. 
’) lower jaw. 
Present at Bi 
2 weeks. 
8 weeks. 
5 weeks. 
5 weeks. 
4 days. 
2 weeks. 
2 weeks. 
4 days. 
:th. 
3-4 weeks. 
12 weeks. 
8 weeks. 
7 weeks. 
8 days. 
3-4 weeks. 
3-4 weeks. 
8 days. 
5 weeks. 
16 weeks. 
12 weeks. 
9 weeks. 
14 days. 
5 weeks. 
5 weeks. 
14 days. 
Permanent 
Dentition. 
J 
11.. 
1 2 .. 
73.. 
£7.... 
PI. 
y p 2 . 
p 3 . 
p 4 . 
Ml. 
M2. 
M 3. 
11 months. 
16 months. 
7£ to 8 mos. 
3| months. 
2 to 3 mos. 
13 months. 
12 months. 
12 months. 
2 months. 
7 to 8 mos. 
17 months. 
12 months. 
18 months. 
9 months. 
9 months. 
5 months. 
14 to 15 mos. 
13 to 14 mos. 
13 to 14 mos. 
5 months. 
9 to 10 mos. 
18 to 19 mos. 
14 months. 
21 months. 
10 months. 
10 months. 
6 months. 
16 months. 
15 months. 
15 months. 
6 months. 
12 to 14 mos. 
21 to 22 mos. 
7. The question now arises as to what may be regarded as 
the cause of this early dentition in modern pigs. We know 
that our present method of feeding causes a rapid develop¬ 
ment of the whole body, including, of course, the head. As 
the teeth could not possibly grow without a corresponding 
growth of the jaws that produce them, we must conclude that 
the development of the skull is the primary cause or driving 
force in their development. Unconsciously the modern feeder 
has produced here some highly interesting facts, instructive 
to natural science at large. Hitherto zoologists have been of 
the opinion that the form of skull of a fixed species is un¬ 
changeable from generation to generation, we may say for 
thousands of years. This is correct as long as we think of in¬ 
dividuals raised in the freedom of nature and under natural 
and similar circumstances. But domestication, with its forced 
feeding and breeding for various demands, has brought about 
