ee thly Microscopical 
Journal, Sept. 1, 1870. 
168 PROGRESS OF MICROSCOPICAL SCIENCE. 
the organisms was strictly observed. As far as practicable, a part of 
the poisonous solution, equal to the amount of fluid on the slide, was 
in every case added. It was found that when two drops of the former 
were added to one drop of the latter, the effect was much more marked 
than when equal parts were brought in contact. This was of course 
to be expected, two drops containing double the quantity of poison in 
one drop, though the degree of dilution was the same. It will be ob- 
served in the subjoined Table that the spermatic filaments are capable 
of existing in a very concentrated solution of common salt (jth). In 
more dilute solutions, as +} 5th to 31,th, their movements are greatly 
accelerated. I was not aware, when experimenting with this substance, 
that the same effects had been observed by Quatrefages, Newport, and 
others. It will be observed, also, that the various poisons were al- 
lowed to act on the organisms for a uniform period of time—i.e. the 
spermatic filaments were kept immersed for fifteen minutes in every 
case; so also were the entomostraca; and though the regularity of 
the data is disturbed by the infusoria having been allowed only two 
minutes’ immersion, still the relative effects of the various solutions 
in a given time is shown: the object being to ascertain, in the case of 
each distinctive poison applied separately to the different genera of 
organisms, the exact quantity requisite to destroy them in a definite 
time. 
TABLE SHOWING THE QUANTITY oF yARIOUS SUBSTANCES IN AQuEOUs SOLUTION 
REQUIRED TO KILL, IN A GIVEN TiME, SPERMATOZOA, LyFUSORIA, AND ENTO- 
MOSTRACA. 
Ento- 
| mostraca, Remarks. 
Substance. Sperma- Infusoria. 
Peel Average. 
if eane sited [ALE Det | 
aa tt 1-30000 | 1-450 | 1-8000 | 1-12816°6. The movements of the in- 
Hydrate of Pe cag ee ci nay 
ARSED 1 oe 1-18000 1-8000 1-2000 1-9333°3 
Nitric acid | 5 1-—18000 1-1500 1-300 1-6600 
Hydrochloric acid . 1-15000 | 1-2000 | 1-300 1-5766°6 
Sulphuric acid.. .. 1-15000 1-1500 1-500 1-5666°6 : 
Alcohol .. .. .. | 1-12500 | 1-750 | 1-2000 | 1-5083°3 | g ie dying make 
Bichloride of mercury | 1-7000 1-6000 | 1-1500 1-4833°3 | An entomostraca lived for 15 
Nitrate of silver .. 1-6500 1-6000 1-2000 1—4833°3 minutes in 1-2000, and was 
Acetic acid ( “iia fie 1-10000 | 1-500 1-50 1-3516°6 removed quite lively. 
Oxalic acid oe 1-7500 1-1500 1-1500 | 1-3500 
Chloride of zinc wo 1-7500 1-600 1-500 1-2866°6 
Picric acid ae 1-3700 1-450 1-2000 1-2050 
Tartrate of antimony 1-4000 1-450 1-500 1-1650 Infusoria when dying make 
Hydrocyanic acid .. 1-5000 1-250 1-500 1-1583°3 short and sudden darts. 
Carbolic acid .. .. 1-1000 1-750 1-1500 1-1080°3 
Camphor .. .. 1-2500 1-400 1-250 1-1050 
aineiage of iodine . 1-500 1-400 1-500 1-466°6 hie struggle vio- 
lution of chloride 2 | lently from the time the 
oflime.. .. ..$| 17000 ano ve 1-350 are put in the solution. 2 
Commonealt .. .. 1-10 1-50 1-100 1-53°3 ge ren are wae very 
lively by weaker solutions 
Average. | Average. Average. 
i 1-7079-47| 1-1676"3, 1-1168°79 of common salt. 
Time 15 m./Time 2 m. Time 15 m. 
A Testimonial to Professor Morris.—Professor John Morris, F.G.S., 
of University College, London, has received from his several admirers 
a testimonial and upwards of 600/. A meeting was convened on the 
14th July, at the apartments of the Geological Society, Somerset House, 
