52 
The Presidenfs Address. 
gland going on at tlie same time as the ova^ it could not be 
said to be proved. This Mr. Sanders^s paper was intended 
to do, and if the facts he gave are considered sufficient, the 
question may be considered settled. There is, Mr. Sanders 
believes, no instance in nature, except in the case of Gastero- 
poda, in which the two zoosperms and ova are produced in 
the same gland ; in all other hermaphrodite animals there is 
a separate gland for each. 
Mr. Sanders tells me his paper is but an instalment, and 
he proposes from time to time, as materials offer, to send to 
the Society notes on the process in different classes of 
animals. 
Mr. Jabez Hogg has contributed a valuable paper on '^The 
Vegetable Parasites of the Human Skin -/^ the object of which 
was to show that vegetable parasites do not produce the diff'e- 
rent varieties of skin disease ; but that when certain diseases 
already exist, the fungi finding a suitable soil, greatly 
aggravate and often change the type of disease; that these 
diseases are always associated with neglect of person, dirt, 
bad air, want of light, and sufficient nourishment ; that the 
spores of fungi are always floating about in the atmosphere, 
and thus ever ready to be deposited and take root in a favor- 
able soil. Of this Mr. Hogg gave many illustrations, and 
showed that although yeast, penicillium, aspergillus, and 
some other fungi, had been separately classed, nevertheless 
they could be made to pass through the same changes, and 
produce ferments that could not be recognised one from the 
other, and therefore 'diff'erence of form he believed to be 
entirely due to the soil or nourishment supplied, and depen- 
dent on such circumstances as whether the growth of the 
fungi takes place in a sickly plant, a saccharine solution, or 
an animal tissue. 
Mr. Erasmus Wilson, F.E.S., who has devoted much 
thought to this subject for a number of years, entertains dif- 
ferent views on this subject, and views which commend them- 
selves to the attention and inquiry of microscopical observers. 
He states that in an unhealthy state of the body and skin the 
epidermis is produced unhealthily ; that one of the forms of 
unhealthy condition is their persistence of the nutritive 
granules of the epidermis in the crude and foetal state, and 
that in this state they take on the process of proliferation, by 
means of which the substance of the rete mucosum is con- 
verted into a phytiform tissue, composed of cylindrical shafts, 
simple and branched, and granules, and that it is to the 
granules that the term sporules has been applied. According 
to him, therefore, the parasite theory of cutaneous disease has 
