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LYMPHATIC AND 
the emission of light from the eyes of some 
animals, independently of the reflexion of in- 
cident light. The ape in question is nocturnal. 
The luminousness of the eye was seen by 
Rengger only when there was total darkness ; 
and then the light was so brilliant that objects 
at the distance of a foot and a half from the 
eye were distinctly seen.* In commenting on 
this statement by Rengger, Treviranus remarks,+ 
“that the intensity of light may be increased 
by the brilliant tapetum of the eye, while it is 
concentrated as in a concave mirror, cannot be 
doubted. But it is impossible that a feeble 
light so concentrated should illuminate objects 
placed at the distance of a foot and a half from 
the eye of this ape, in a dark place.” The 
same physiologist seems to be satisfied that 
some dogs also have a similar power of gene- 
rating light within their eyes. In these, he 
States, the light is seen only when an impres- 
sion on the sight or hearing arouses the ani- 
mal’s attention, or when he is excited by the 
operation pf some instinct or passion. 
We are, therefore, constrained to conclude 
that this subject is still open for elucidation by 
future inquirers. If it should be proved that 
some of the higher animals really do emit 
light from their eyes, independently of the in- 
cidence and reflexion of that from without, it 
will go far to render it probable that, in lumi- 
nous animals generally, the development of 
light depends more upon the movements of 
some imponderable agent in and from their 
nervous system, than upon the nature of the 
composition of the fluids poured out by the 
luminous organs. 
Another series of phenomena, intimately 
connected with, and illustrative of, those previ- 
ously considered, demands notice here, namely, 
the shining of fishes, and other animal bodies 
shortly after death. The luminousness of dead 
fishes isa very common subject of observation, 
but not on that account the less worthy of par- 
ticular attention. It has been ascertained that 
the light is given out from every part of the 
body, external and internal, that is exposed to 
the air ; and that on the surface of the luminous 
parts there is a slight moisture, or solution of 
the tissues of the animal, which can be scraped 
off, or diffused in water, and continues lumi- 
nous for a short time after being so removed. 
When pieces of the skin or muscle of a fish 
are placed ina little water, the luminousness 
appears only on the surface when the water is 
at rest; but whenever it is agitated the light is 
diffused through the whole body of water. 
In some fishes, as the whiting, this lumi- 
nousness appears within a very short time after 
death ; in others, not for some days; but in 
all it ceases before the truly putrefactive process 
has commenced. It is observed that those 
fishes which most quickly putrefy, are also 
those which give out light the soonest. 
From the circumstance mentioned above, 
that this luminous fluid formed on the bodies 
of dead fishes is miscible with water, and re- 
* Rengger’s 
Paraguay, s.3 
+ Biologie, i, 439, 
os oe der Saugthiere von 
LACTEAL SYSTEM. 205 
tains its luminousness fora short time after 
being so mixed, it has been concluded that the 
beautiful phenomenon of the phosphorescence 
of the sea may be frequently owing to the pre- 
sence, in great quantity, of the remains of fishes 
recently dead. It is certain that the magst 
careful observers sometimes fail to detect any 
entire living animals in sea water taken up 
from a brilliantly luminous sea; and find only 
abundance of small fibres and shreds of what 
seem to be broken-down animal tissues. Pro- 
fessor Smith* concluded from his own obser- 
vations made in the Atlantic, that, while the 
bright sparkling light of the surface of the 
ocean is always emitted by living animals, that 
duller diffused luminousness, which is fre- 
quently seen over a vast extent of the sea, 
giving it the appearance of milk, is given out 
by “a dissolved slimy matter, which spreads 
its light like that proceeding from phosphorus.” 
Under the most powerful microscope, Smith 
saw nothing in such water but “the most mi- 
nute glittering particles, having the appearance 
of solid spherules.” Humboldt saw a great 
extent of the surface of the sea rendered almost 
gelatinous by the admixture of numbers of 
dead dagyse and meduse. 
It may, therefore, be regarded as probable, 
at least, that the luminousness of the ocean is 
sometimes caused by dead matter; but it is 
certain that, in the great majority of instances, 
it is entirely owing to the presence of living 
animals, possessed of the light-giving property.+ 
In attempting to examine these, so as to deter- 
mine their forms and habits, it is important to 
keep in mind that they are sometimes ex- 
tremely small, so as to be distinguished with 
considerable difficulty, even with the aid of the 
best microscopes. And when they are larger, 
they are frequently so transparent as to elude 
notice. 
BIBLIOGRAPHY.—Canton, Phil. Trans. 1769. 
446. Macartney, Phil. Trans. 1810. 2. Spallan- 
zani, Mem. della Soc. Ital. vii. 271. Macaire, 
Mem. sur les Lampyres, in Jour. de Physique, 
xciii. 46. Humboldt, Reise i. 109. Todd, Jour- 
nal of Science, 1826. 241. Murray, Experimental 
researches, 1826, Kirby and Spence, Introd. to en~ 
tomol. ii. 256. Quoy and Gaimard, Ann. des Sc. 
Nat. iv. 1, Tiedemann, Comp. physiol. i. 257. 
Macculloch, Phosphorescence, in Edin. Encycl. xvi. 
1823. Burmeister, Manual of entomol. by Shuck- 
hard, 494. Muller, Physiology, by Baly, vol. i. 
ed. 2, 1839. 
LUNG.—See Putmonary OrGans. 
LYMPHATIC AND LACTEAL SYS- 
TEM, —(Fr. Systéme lymphatique; Germ. 
Saugadersystem oder Lymphgef dsssystem. 
* Tuckey’s Voyage, 258. 
+ Martin, Canton, Hulme, and others supposed 
the luminousness of the sea to be caased bya phos- 
phorescent oil, generated during the putrefaction of 
animals. Silberschlag regarded it as phosphoric. 
Mayer, Beccaria, Monti, Brugnatelli, and others, 
believed it to be owing to the giving out of light 
imbibed from the sun’s rays. Bajon, Delaperriere, 
and Gentil imputed it to electrical agency, because 
it is excited by friction. Foster supposed it to be 
sometimes electric, and sometimes putrefactive. 
