26 
Proceedings of the Royal Irish Academy. 
grow old, and nearly all escape the diseases that trouhled them when 
the types were made of lead only, still the trade is regarded as trying 
for boys ; and had legs are not unknown. In some instances it would 
appear that the needless and harsh custom of compelling a standing 
posture whilst at work may he an efficient cause. 
In the atmosphere of type fotmdries, and in that of stereotypers, the 
antimony is likely, however, to be present in quantity sufficient to 
affect the constitution of operatives. 
Stable A ir (Plate IX.). — The deposit on a beam seven and a-half feet 
above the stable floor was brownish in colour, and somewhat tenacious, 
from the presence of long fibres. Microscopically examined, I found that 
almost all this atmospheric sediment was of animal matter. There 
were a few moth scales, a few ovules, some of them probably of moths. 
I found a small whitish larva encrusted in a sheath of agglutinated 
dust, and an acarus, different somewhat from those described. It was 
in colour whitish ; its legs were not red, but white ; hair decidedly 
simple, not feathered on legs; that from the body was apparently 
jointed Equisetum. To a morsel of rent cotton fibre, that came 
from the groom's shirt, no doubt, were accidentally attached a couple of 
small heads of minute fungi, a species of Botrytis, resembling Botrytis 
urticce. 
Fragments of the fine horse hair were common, and there was a 
multitude of cuticle cells sent about in the atmosphere when the 
horse was being currycombed and brushed. 
Grooms who do not continually abide in such an atmosphere pro- 
bably escape without any particular hurt; though sometimes it is 
evident they may get awkward matter into their lungs. As it is ma- 
nifest that larhers must live in an atmosphere very closely resembling 
this — with human cuticle, scales, and hair present, instead of equine — 
I took an opportunity of inquiring about their diseases. I found that 
they suffered rather usually from chest complaints, and that the ' ' ma- 
chine," or rotatory brush, whirls off a dust of no pleasant character, 
about the level of the breath. 
Dissecting-room Air (Plate IX.). — The next atmosphere to which J 
shall draw attention is that of the dissecting hall. The dust was taken 
from ledges from seven to eight feet high. It was dark-brown, and some- 
what tenacious, with some fibres. Microscopically examined, I dis- 
covered in it fragments and fibres of white fibrous tissue, of yellow 
fibrous tissue, fibrillae of striated or voluntary muscle, and of non- 
striated or involuntary muscle. Treated with nitric acid, the latter 
corrugated in a characteristic manner. Besides these, there were frag- 
ments of cuticle^ — epithelial scales — inchoate particles and corpuscles 
of various sizes. Some appeared to be fat cells, whilst some others 
may have been blood corpuscles. There were a few fragments of hair. 
This is a somewhat ghastly revelation. I^evertheless, it is better 
to have the truth known, when precautions, now neglected, may be 
taken. It is clear that it would be perilous for students with abraded 
or diseased lungs to undertake the study of anatomy. It has been said, 
