Page 80, line 22, after microscope add by
Page 88, three lines from bottom, for improvent read improvement
Page 95, line 2, for R read K
Page 111, two lines from bottom, for VK read VX
Page 115, line 12, for g read q
Page 125, note, for Fig. 13 read Fig. 13*
Page 145, line 17, for cast of read cast-off
Page 153, line 21, for unkown read unknown
Page 169, eight lines from bottom, for is read are
Page 188, note line 9, for preventatives read preventives