610 Original Articles. [Oct., 
organic particles, both of which seemed to float in a gelatinous film 
somewhat resembling balsam. Several small cysts, coloured green, 
were also visible. On adjusting a higher power (200 diameters*), and 
covering a portion of the thin glass, this gelatinous film proved to 
consist “entirely of transparent colourless ‘“monads,” possessing no 
locomotion, but exhibiting a slight tremulous movement. 
I carefully poured back the water into the vessel, and left it until 
the day following, when, on examining the water, I found it to swarm 
with “‘monads.” Even those under the covering glass, which I had 
left undisturbed the day previous, were locomotive and very active. 
In their forms and movements they resembled various kinds of 
infusoria, some moving forward with a rapid rotatory motion; 
others swinging to and fro, progressing more slowly; and others 
again reminding the observer, by their movements, of the loricated 
infusoria. Some were globular; others, ovate ; and others again, flat- 
tened discs. Many were undergoing longitudinal subdivision, and 
the largest were about 1-700th of an inch in diameter. Transparent 
vegetable fibres were also present, and these were covered with sessile 
‘“‘monads ;” some cysts appeared to have discharged their contents, 
and were floating empty in the water. At this period, my investiga- 
tions and experiments, which had been long protracted, were brought 
to a close. 
Was it possible, I would ask, that these swarms of living organ- 
isms (to whatever groups they may have appertained) could have 
been spontancously produced in a single day from the particles of 
organic matter which, along with the mineral molecules, were 
imbedded, as it were, in their aggregated mass? Or is it not more 
likely that the deposit of dust contained, besides vegetable and mine- 
ral particles, a vast number of zoospores, requiring but warmth and 
moisture. to call them into active life? Which is the most rational 
and scientific method of accounting for their appearance, whether 
our judgment be based upon theory or experiment ? 
Let me now add a few of the general results of my prolonged 
investigations to the special cases already named. 
In the course of my experiments with distilled water, I have 
carefully and repeatedly examined,—Ilst, dust taken from window- 
panes, and from other common-place localities at home; in this I 
have found the following forms, of which I have retained more or 
less accurate sketches made at the time of observation :— 
* Cercomonas fusiformis ;’ various Amebe (some of them unde- 
scribed, as far as I can ascertain), one or two Vorticellae, Enchelis, 
Kerona (2), cysts, from which swarms of minute zoospores issued on 
their being broken by pressure, and in one case I found, in pure 
water containing nothing but the usual slight deposit occasioned by 
exposure to the air, what appeared to be “the larval form of one of 
the Entomostraca, of which I have no doubt an ovum had found its 
way into my distilled water. 
* T give the measurements in diameters in all cases, chiefly because ny instru- 
ment is by Schieck, of Berlin, and the English measurements by 1ths, ths, &e., 
are unknown to the foreign makers. 
