476 
NATURE 
e 
[ Sept, 17, 1885 
marked the practical close of one great series of controversies. 
The discussions of the present meeting will, I trust, result in the 
recognition and clear statement of a number of other equally 
important problems of Highland geology which still await solu- 
tion. AndI am sanguine enough to hope that when this Asso- 
ciation next gathers here, my successor in this chair will have to 
congratulate his audience upon a very brilliant retrospect of work 
actually accomplished in the interval. 
I am encouraged in this optimism by the fact that in the period 
which has elapsed since our last meeting here, great and import- 
ant improvements have been made in the methods of geological 
investigation. We have seen how the discovery of a few frag- 
mentary shells in the limestone of Durness, and of sundry casts 
of bones in the sandstone of Elgin, have been the means of 
profoundly modifying our ideas concerning the age of vast tracts 
of rock in the Highlands. The development of modern 
methods of petrographical research is destined, I believe, to lead 
to a similar revolutionising of our views concerning the wonder- 
ful series of changes which have taken place within rock-masses, 
subsequently to their original accumulation. 
Especially does the application of the microscope to the study 
of rocks, when employed in due subordination to, and illustra- 
tion of, work done in the field, promise to be the source of 
valuable and fruitful discoveries in the field of Highland 
geology. 
In connection with this subject. I cannot refrain from remind- 
ing you that while the initiative in the application of the palz- 
ontological method of research was taken by an English land- 
surveyor, we are indebted to a Scotchman in an equally lowly 
station of life, for overcoming some of the first difficulties in 
connection with petrographical study. Many microscopists had 
employed their instruments, and sometimes with useful results, 
in the study of the powders and the polished surfaces of rocks ; 
but it is to William Nicol, of Edinburgh, the inventor of the 
well-known polarising prism which bears his name, that we owe 
the discovery of the method of preparing transparent sections 
of fossils, crystals, and rocks, whereby their internal structure 
may be examined by transmitted light. Nicol bequeathed his 
preparations to his friend Alexander Bryson, and some of them 
are now preserved in the British Mu-eum. It is interesting, 
too, to recall the circumstance that it was a thin section of the 
granite of Aberdeen in the collection of Bryson which exhibited 
to Sorby that wondrous assemblage of minute cavities containing 
liquids, and led him, shortly before our previous meeting here, 
to write his paper ‘‘On the Microscopical study of Crystals, 
indicating the origin of Minerals and Rocks’’—a paper which 
has indeed proved epoch-making in the history of geology. 
Before concluding the remarks which hy your kindness I have 
been permitted to offer you to-day, I cannot forbear from in- 
dulging in a pleasant reminiscence of a personal character. 
Nearly fifteen years have passed away since I first visited the 
Highlands for the purpose of geological study ; it was at that 
time I first found myself at liberty to put into practice a scheme 
cherished by me from boyhood, that of studying those Secondary 
rocks and fossils of the Highlands among which such valuable 
pioneer work had been done by JohnMacculloch, Roderick Murch- 
ison, and Hugh Miller. I had endeavoured to prepare myself for a 
somewhat difficult task, by a training partly unofficial and partly 
official—I will not employ the terms ‘‘amateur’’ and “* profes- 
sional,” for of late they have been so sadly misused —-but when I 
came a stranger among you, I could not have deserved, and I 
certainly did not anticipate, that cordial welcome, that kindly 
aid and that generous appreciation, of which I accept my position 
here to-day as the crowning manifestation. 
While I continue to occupy myself with the glorious problems 
of Highland geology—and hitherto I have found that each diffi- 
culty surmounted has resulted, like the sown teeth of the 
slaughtered dragon, in a plentiful crop of new ones—the many 
acts of kindness of my numerous friends here can never cease to 
be present in my mind. For not only am I indebted to those 
who, like your own Dr. Gordon, of Birnie, and Dr. Joass, of 
Golspie, have been able out of stores of their knowledge to 
furnish me with ‘‘ things new and old,” and who have been un- 
failing in their aid and sympathy, but to those also who have 
pitied, but nevertheless helped, the ‘‘daft callant that speers 
after the chucky stanes.” 
I know of no higher pleasure than that which the geologist 
experiences in visiting regions of great scientific interest which 
are new to him, and of grasping the hands of fellow-workers, 
whose labours and teachings he has learned to admire and to 
| 
appreciate. Whatever may be my lot in this way in future years, 
however rich the country visited may be in objects of profound 
instructiveness or of surpassing interest, I can anticipate or 
desire nothing more valuable than the lessons, or kinder than the 
reception which I have met with here. 
“T’ll ask na mair, when I get there, 
Than just a Hzedax welcome.” 
SECTION D 
BIOLOGY 
OPENING ADDRESS BY ProF. W. C. McInTosH, M.D., LL.D., 
F.R.Ss.L. & E., F.L.S., Cor. M.Z.S., PRESIDENT OF THE 
SECTION 
I HAVE selected the subject of the phosphorescence of marine 
animals for a few remarks on the present occasion—the theme, 
perhaps, being the more appropriate from its congenial local 
surroundings ; for, like St. Andrews, Aberdeen is an 
“ Old University town 
Looking out on the cold North Sea.” 
A phenomenon so striking as the emission of light by marine 
organisms could not fail to have attracted notice from very early 
times, both in the case of navigators and those who gave their 
attention in a more systematic manner to the study of nature. 
Accordingly we find that the literature of the subject is both 
varied and extensive—so much so, indeed, that it is impossible 
onthe present occasion to give more than a very brief outline of 
its leading features. This is a subject of less moment, however, 
since the great microscopist, Ehrenberg, in his treatise, “ Das 
Leuchten des Meeres,” published by the Berlin Academy in 
1835, has given a very full account of the early literature on 
phosphorescence, both in marine and terrestrial animals, no less 
than 436 authors being quoted. The limitation just mentioned 
is therefore sufficiently warranted. 
Though it is in the warmer seas of the globe that phosphor- 
escence is observed inits most remarkable forms—as for instance 
the sheets of white lizht caused by octiduca, and the vividly 
luminous bars of Pyrosonza—yet it is a feature which the British 
zoologist need not leave his native waters to see both in beauty 
and perfection. Many luminous animals occur between tide- 
marks, and even the stunted sea-weeds near the line of high 
water everywhere sparkle with a multitude of brilliant points. 
As a ship or boat passes through the calm surface of the sea in 
summer and autumn, the wavelets gleam with phosphorescent 
points, or are crested with light; while the observer, leaning 
over the stern, can watch the long trail of luminous water behind 
the ship, from the brightly sparkling and seething mass at the 
screw, to the faint glimmer in the distance. On the southern and 
western shores, again, every stroke of the oar causes a luminous 
eddy, and sone of the smaller forms are lifted by the blade and 
scintillate brightly as they roll into the water. The dredge and 
trawl likewise produce, both in the shallower and deeper parts 
of our seas, many luminous types of great interest and beauty. . 
I shall, in the first instance, glance at the various groups of 
marine animals which possess the property of phosphorescence, 
and thereafter make some general remarks on the subject. It is 
found then that this feature is possessed by certain members of 
the Protozoa, and by the following groups of the Metozoa,—viz. 
Ccelenterates, Echinoderms, Worms, Rotifers, Crustaceans, 
Molluscoids, Mollusks, and Fishes. 
About the middle of last century Baster found that at least 
three species of what he called microscopic animalcula (** Opuscula 
Subseciva,” vol. i. p. 31, table 4, Fig. 1), apparently infusoria. 
were phosphorescent; and fully half a century later, Pfaff 
noticed that the luminosity of the sea at Kiel was due to certain 
members of the group just mentioned. Subsequently both 
Michaelis and Ehrenberg met with phosphorescent infusoria in 
the Baltic, the latter describing them as species of Peridinium 
(now Ceratium) and Prorocentrum. The same fact, associated 
with the absence of Mocéé/uca at Kiel, has again more recently been 
brought forward by Stein. In our own seas I have been es- 
pecially struck with this feature in July and August, the whole 
surface of the sea along the eastern shores of England and 
Scotland teeming with Ceratium and Peridinium, besides other 
Infusoria, which form a greenish scum on the interior of tow-nets 
in inshore water, and for many miles seaward. As the waves 
curl {rom the sides of the boat in quiet water, the crest of each 
| sparkles with multitudes of luminous points, which gleam for a 
