Transcriber’s notes:

In this transcription a black dotted underline indicates a hyperlinkto a page, illustration or footnote; hyperlinks are also marked by aquahighlighting when the mouse pointer hovers over them. A red dashedunderline indicates the presence of a concealed comment which, in thehtml version, can be revealed by hovering the mouse pointer over theunderlined text. Pagenumbers are shown in the right margin. Footnotes are located at the endof the book.

The text contains typographic characters that will not necessarilydisplay correctly with all viewing devices. If some of the characterslook abnormal, first ensure that the device’s character encoding isset to Unicode (UTF-8). The default font might also need to be changedto a Unicode font such as Arial Unicode MS, DejaVu, Segoe UI Symbol orFreeSerif.

Many of the illustrations in the book were of poor quality and afew had no visible useful information. Where possible, they have beenenhanced to clarify the details. Alphabetic labels in the illustrationsoccasionally differ from those stated in the accompanying captions.Some illustrations have been relocated closer to the relevant text andthe list of illustrations has been amended as necessary.

Discrepancies between the Table of Contents and headings in the body ofthe text are as in the original. Inconsistencies in the use of singleand double quotation marks are as in the original; other punctuationanomalies have been corrected silently. Missing degree (°) symbols havebeen inserted where necessary.

Minor spelling inconsistencies are as in the original, e.g.tetanising/tetanizing, Das/Dass, but the following overt spellingerrors have been corrected silently:

his —> this
despressing —> depressing
presistent —> persistent
actic —> lactic
excitabilitty —> excitability
Zephyanthes —> Zephyranthes
fal —> fall
tranmission —> transmission
substracting —> subtracting
issue —> tissue
conducing —> conducting
ummasking —> unmasking
be —> been
end —> and
flexture —> flexure
tentanising —> tetanising
anisotrophy —> anisotropy

The cover image of the book was created by the transcriber and isplaced in the public domain.