308 
NATURE 
(Feb. 16, 1871 

thesising the colours of the spectrum by reflection from seven 
moveable mirrors. With the mirrors placed at equal distances 
from each other, the spot of compound light is not white but 
yellow, that is to say, it is yellowish white, the colours lost 
between the mirrors being just those necessary to bring out the 
full white. 
C. J. WoopWARD 
Meteor 
A FINE meteor was seen here to-night at about 9.10 P.M. ; it 
was described to me as starting from near @ Orionis, and pro- 
ceeding towards a point a little north of y Eridani, when it was 
lost behind a belt of cloud. J. M. WILson 
Rugby, Feb. 13 
Snake Bites 
In NATuRE of Dec. 22 I notice a note extracted from the 
Pall Mall Gazette, giving a return of the excessive number of 
deaths which take place annually in the Bengal Presidency, from 
the effects of snake-bite. That 11,416 persons die from this 
cause alone, ‘‘and that no efficacious means are adopted to check 
its ravages,” are very startling announcements, and strike me 
as being well worth the attention of the readers of NATURE. 
Upwards of a year ago Dr. Fayrer recorded an elaborate series 
of experiments on snake poison, in the /zdian iledical Gazette, 
from which he concludes ‘that if an animal, and probably a 
man, be fairly bitten by a fresh and vigorous cobra or daboia, it 
or he will inevitably succumb unless some immediate or direct 
method of arresting the entering of the poison into the circula- 
tion be practised.” This direct method is to apply ligatures and 
cauterisation ; for, says the same authority, ‘‘to conceive of an 
antidote, in the true sense of the term, to snake poison, one must 
imagine a substance so subtle as to follow, overtake, and neutra- 
lise the venom in the blood, or that shall have the power of 
counteracting and neutralising the deadly influence it has exerted 
on the vital forces.” I remember reading some time ago of 
another doctor in India or Australia, who had tried ammonia as 
an antidote, but I cannot recollect with what result. It seems to 
me, however, that this real antidote has still to be found: and 
cauterisation, to prove effectual, must follow the course of the 
poison, which it cannot do; nor, indeed, is it possible for it to 
do much more than burn the walls of the wound, so it is not to 
be wondered at if some of those subjected to this powerful treat- 
ment do not recover. 
I have long thought that the best cure for snake-bite would be 
powerful suction, applied to the wound by means of an instru- 
ment made for the purpose, and similar in principle to a boy’s 
sucker. This would draw off a considerable quantity of the 
plood in the neighbourhood of the wound, and by so doing wash 
the poison out before it. Above the wound there might be a 
ligature applied, but sufficiently distant from it to ensure that the 
blood in the small vessels between the wound and ligature be 
competent to wash out the poison. 
Where such an instrument is not at hand, and the assistance of 
a second party can be obtained, he might tie a ligature above 
the wound, and suck the latter with his mouth for a considerable 
time, spitting out all the saliva and blood which accumulates. It 
would be advisable, too, to make the wound a little larger before 
commencing to suck, with a sharp knife or otherwise, in order 
that the greater flow of blood may the better discharge the 
poison. ‘The operation of sucking the poison into the mouth 
need not be feared, for even although a small portion of it were 
swallowed, it could do no harm. I believe I am correct in 
stating that a quantity of poison which will prove fatal on entering 
the circulation, would have no injurious effect when taken into 
the stomach. Where the bite is in such a part of the body that 
the party bitten can easily suck it himself, then he ought to do 
so: but unfortunately this is seldom the case, it usually being the 
lower extremities which are attacked. 
In support of this method, I may say that I read, two or three 
years ago, an account of how the bites of snakes were counter- 
acted in a woody portion of South America. The writer said 
when any one was bitten—and there were one or two almost 
daily—he was sure to die in thirty minutes to one hour after- 
wards if his wound was not immediately sucked. There, how- 
ever, in order to make quite certain that the poison, when sucked 
out of the wound, would have no injurious effect on the sucker, 
the latter filled his mouth with olive oil betore applying it to the 

wound ; and I imagine this would be a sure precaution, for it 
provides a plentiful supply of matter for the poison to diffuse 
in, without interfering much with the absorbents of the mouth. 
The result of this writer’s experience was that the bitten 
person seldom, if ever, died; and he who sucked the wound 
never felt an injurious effect. 
This subject seems so important that I have ventured to ad- 
dress you at this length upon it, in the hope of drawing from 
some of your correspondents further details concerning antidotes 
and methods of curing snake-bite. T. L. PATTERSON 

The Cretaceous Period © 
In Nature of Jan. 19, a letter appeared from Prof. Wyville 
Thomson defending the expressions, ‘‘ we are still living in the 
Cretaceous epoch,” ‘‘ ¢#e chalk is being formed at present in the 
bed of the Atlantic.”” When first this announcement was made, 
it was followed up by various strong comments implying that the 
similarity of the Atlantic mud to the chalk in lithological cha- 
racter, and in many of the imbedded organisms * ‘* would seem 
to unsettle much that has generally been accredited to Bore 
cal science,” would, in fact, revolutionise geological classification. 
As these unfortunate expressions are again put forward, not- 
withstanding the protest of our most distinguished geologists, + 
Sir Roderick Murchison and Sir Charles Lyell,} it may be use- 
ful to consider what the question at issue really is. Simply stated, 
it is this: Have we sufficient evidence for drawing one of our 
strongest lines at the base of the tertiary deposits, and saying 
that it marks the commencement of a new epoch or period ?§ 
In grouping the rocks, we have been obliged frequently to 
adopt an arbitrary classification. The thickness will not furnish 
the necessary tests, as accumulation is more rapid at one time 
and place than another. Lithological character will not do 
alone, as a bed often passes both vertically and horizontally into 
one quite different. The organic remains will not do alone, as 
the fauna migrated and re-migrated to suitable areas when fayour- 
able conditions recurred. 
But sometimes we have the commencement of a new period 
well defined by seeing that the group of deposits which form 
the record of it rest unconformably on an older formation, which 
has been in part at least heaved up, denuded, and used to form 
the new series. At the bottom of this newer series we must 
infer a considerable break—a portion of unrepresented time. || 
This time may be represented elsewhere, but we have a point in 
time well marked by the first grain of the new deposit laid upon 
the older denuded rocks. 
So we are quite safe in saying that there had been a considerable 
lapse of time, and that new conditions prevailed over large areas 
when the Cambrian was laid unconformably upen the Laurentian, 
when the Upper Old Red was laid unconformably on the Lower 
Old Red and Silurian, when the Permian was laid uncon- 
formably on the Carboniferous and more ancient rocks. 
Probably deposition went on longer over one area than 
another—very likely deposition has never in the earth’s true 
geological history been entirely arrested, so that the connecting 
deposits between any two formations and intermediate forms of 
life may possibly still be preserved under the depths of ocean or 
on the vast still unexplored continents. It would be of course 
difficult under such circumstances to identify in a series of more 
or less continuous deposits the base line we have so well marked 
elsewhere by visible unconformity ; and this difficulty occurs in 
the older rocks, as, for instance, in the case of the base of the 
Upper Old Red or Carboniferous in South Wales, of the Per- 
mian when the Rotheliegende is present, and many others, but this 
arises from our want of data. We might fairly hope that if we 
could find the continuous deposits after enormous intervals re- 
presented by known unconformities, we should read a wonderful 
story, 2nd know, for instance, more clearly by what variation of 
forms and invasion of stronger life from adjoining areas we 
are left at the end of a long period with an ammonite instead of 
a goniatite, or a nautilus instead of either. 
Now, to return to the particular case under notice. Have we 
at the bottom of the Tertiary formations evidence of a break so 
large, of a lapse of unrepresented time so long, of a change in 
conditions over large areas so great that, we are justified in saying 
that this is a convenient place to draw one of our strong lines ? 

* Carpenter, Lecture Royal Institution, Ap. 1869. 
+ Pres. Add. Geog. Sect. B.it. Assoc., Liverpool, 1870, 
t Students’ Elements of Geology, 1871. 
§ See alsoan able article by Mr. Green, Geol, Mag., Jan. 1870. 
|| See Ramsay, Pres. Add. Geol. Soc., 1863-4. é 
