1 12 
Notices of Books . 
[January, 
notice of Pettenkofer’s recent investigations on “ ground-air” 
and its passage into our dwellings. The remaining two chapters 
may be considered biological rather than physical or chemical. 
They treat of spontaneous generation, of minute organisms pre- 
sent in the air, and of the researches of Schwann, Schultze, 
Schrmder and Dusch, Pasteur, Pouchet, and Bastian. Con- 
cerning the conclusions of the latter author, we must call atten- 
tion to the fadt, that however decisively it might be proved that 
solutions of organic matter subjedt to temperatures above the 
boiling-point of water in sealed vessels were subsequently found 
to contain living organisms, not introduced from the atmosphere, 
such a result can throw no light on the first appearance of vege- 
table and animal life. On the primordial globe, before plants and 
animals existed, there can have been no organic matter. To prove the 
reality of spontaneous generation, it will, therefore, be necessary 
to produce low forms of organic life from purely inorganic matter, 
atmospheric germs being, of course, excluded by precautions 
similar to those adopted by Pasteur. 
In connection with the important subjedtof ventilation and the 
influx of ground air into our dwellings, Mr. Hartley gives from 
his own observation the following interesting fadt : — “ A 
remarkable case in a London house has come to my knowledge, 
which gives a distindt proof of the much greater passage of gases 
through the walls in winter than in summer. A small room, occa- 
sionally used, was noticed sometimes to have an unbearably bad 
smell ; this was never noticed in summer nor in winter unless a 
fire was lighted in the room ; the drainage was suspedted and 
examined, but was found perfedl, yet here was this extraordinarily 
foul air making its way into the room whenever the interior was 
warm and the exterior cold. The cause was a dust-bin built 
against one of the walls, and the filtration of the air through this 
and the house-wall into the room.” In passing, we may here 
remark that in all “ closetted” towns, the “ dust-bin” is an evil 
with which sanitary reformers scarcely know how to deal. It 
often contains matter which cannot be forced down the soil-pipe, 
and which is yet little less offensive than true sewage matters. 
It is no pleasant thing to have a heap of cabbage leaves, parings 
of vegetables, oyster-shells, fish-bones, &c., fermenting in close 
proximity to a dwelling house. Another point which naturally 
suggests itself in connedlion with the subjedt of “ ground-air,” is 
the danger which may follow from the adoption of asphalte road- 
ways. These being impervious to air, the sewage gases will take 
the direction of least resistance, z.£.,they will rise up through the 
earth beneath the houses all the more readily on account of the, 
ascending current of warm air within. A sound layer of asphalte 
should extend beneath every house, or else our dwellings, as Dr. 
Richardson proposes in his model city, should be builtupon arches, 
so that the wind may have free play beneath them. Mr. Hartley 
very pardonably expresses a doubt as to the sanitary value of the 
