136 
Correspondence . 
[January, 
movements originally discovered 
by me, rather than to Prof. Marey’s 
interpretation of the manner in 
which those movements are pro- 
duced. This follows because Prof. 
Marey, before replying to the 
Acade.ny, and as the reader is now 
aware, requested me to limit or define 
the extent of my claim upon the 
movements in question : the restrictive 
clause certainly occurs in this con- 
nection. Prof. Marey, not content 
with mixing up two things essentially 
distind, states that in my last work 
(“ Animal Locomotion,” 1873) I de- 
vote ten pages to impugning his 
theory of the flight of birds, and a 
special chapter to show to what ex- 
tent my theory differs from his. 
These pages and that chapter, I may 
remark, were first published in 1870, 
and deal not with the figure-of-8 
theory in its integrity, but with cer- 
tain details which Prof. Marey has 
since modified. When I wrote them 
Prof. Marey ( vide his earlier writings, 
“ Revue des Cours Scientifiques de la 
France et de PEtranger,” March, 
1869) maintained that the wing made 
a backward angle of 45 0 with the ho- 
rizon during its descent , and a forward 
angle of 45 0 during its ascent. This 
view, shown on that occasion (1870) 
to be untenable, has been greatly mo- 
dified in Prof. Marey’s later works. 
Those of your readers who compare 
Prof. Marey’s works with my own, 
and who have perused Prof. Cough- 
trie’s article and examined the parallel 
passages and dates given in your 
journal for April, 1875, will, I be- 
lieve, have difficulty in accepting 
Prof. Marey’s statement to the effect 
that “two authors could not easily 
have treated the same subject with 
more widely dissimilar methods, and 
arrived at more different conclusions.” 
Prof. Marey makes light of the paral- 
lel passages and dates. He says 
Prof. Coughtrie “ compares texts, and 
every time he meets with similar ex- 
pressions in the English and French 
books he raises a cry of plagiarism, 
as if it were possible to treat of the 
flight of birds without speaking of 
wing, child’s kite, inclined plane, 
sculling, &c.” The question, how- 
ever, has its serious aspedt. The pla- 
giarisms, if such they are to be 
designated, are not — as Prof. Marey 
would have your readers believe — 
confined to isolated words ; they ex- 
tend, according to Prof. Coughtrie, 
to clauses and passages, and these 
clauses and passages occupy many 
pages. It is easy to understand how 
two authors can write on the same 
subjedt, at the same time, and express 
the same ideas in different language : 
it is more difficult to comprehend how 
two authors can write on the same 
subjedt, at an interval of nearly two 
years, and express the same views in 
what many will regard as virtually 
the same language. 
J. Bell Pettigrew, M.D., F.R.S., 
Professor of Medicine and Anatomy, 
University of St. Andrews. 
