36 
Structure of the 
t Monthly Microscopical 
Journal, July 1, 1869. 
Fig. 4. 
the humour, and therefore the ciliary processes, as the organs of 
secretion of the vitreous humour, have prohably less reference to 
the nutrition of its structures than the supply of an abundant and 
highly transparent fluid for mechanical and physical purposes. 
It is a general law in the economy that each atom of the body, 
by its inherent vitality, must appropriate and transform for its own 
use whatever nutriment it requires. In accordance with this law, 
it is the part of the structure of the adult vitreous humour to vita- 
lize the histogenetic material which the vitreous fluid contains, for 
the renewal of its elements and the maintenance of its trans- 
parency. Considered in this light, it is dependent on the ciliary 
processes for nutriment only in so far as these organs secrete 
abundantly the vitreous fluid, in which is dissolved a small amount 
of albumen, but which at the time of its secretion is entirely devoid 
of organization. On subjecting a fragment of perfectly fresh 
vitreous humour to the action of dilute nitric acid, the fibres of the 
anastomosing cellular tissue are observed, under a high magnifying 
power, to have strung upon them transparent globules, measuring 
about 5^th of an inch in diameter. These globules are quite dif- 
ferent, but scarcely distinguish- 
able, from the ordinary vitreous 
fluid, and may not inaptly be 
compared to a string of pearls 
(Fig. 4). They consist of a 
viscid, highly transparent fluid, 
and cling to the fibres by their 
own tenacity, or by vital at- 
traction ; they have the form 
of cells, but they are devoid of 
any cell-wall, and the ordinary 
vitreous fluid has no efiect in 
dissolving them; they are so 
closely set as to touch each 
other, and they completely mask 
the view of the fibres which 
they enclose ; and they possess 
a high degree of refrangibifity. 
Spectra of these globules have been long familiar to natural 
philosophers and workers with the microscope as frequent sources 
of interruption to vision in their scientific investigations ; but until 
the present they have eluded the most searching inquiries in the 
dead subject. The reason of this is that a few hours after death 
they spontaneously detach themselves from the fibres of the humour, 
and coalesce into large drops, which in the aggregate have a slightly 
yellowish colour. A convenient method by which an observer may 
see these globules in his own eye is by looking through a lens of 
Pearly globules attached to the cellular tissue of the 
vitreous humour. (Magnified 200 diameters.) 
