165 
NATURE 
[AprIL 18, 1912 
vironment, not to be described as use or injury, but 
broadly classed as excess or defect of heat, light, 
strain, moisture, chemical constituents of food, may set 
up in an organism changes of growth, structure, and 
function of the most striking and obyious character, 
greatly in excess of the apparent magnitude of the 
responsible factor. Take, for instance, such cases as 
that of the rest-harrow grown in dry upland as con- 
trasted with that grown in moist meadowland. 
I also objected (and do so again) to the loose use 
of the word ‘‘stimulus”’ in this connection by Dr. 
Reid. A particular, definite, measurable agent setting 
up by its action on living matter a reaction is, in 
biological terminology, said to stimulate that living 
matter, and both it and its immediate action are called 
‘“a stimulus.’ The exact nature of the stimulating 
activity, whether set up by this or that chemical sub- 
stance, by this or that fluctuation of light, heat, or 
by electrical conditions, is stated with precision, and 
its amount and duration compared with the effect on 
the living matter. To call the nutrition—the normal, 
persistent nutrition of a growing seed or young plant— 
*\a stimulus”’ is inadequate and misleading. A good 
deal of analysis is omitted by so doing. When nutri- 
tion, the necessary normal supply of chemical materials 
in the presence of which a seedling grows and unfolds 
or develops its specific qualities, is described baldly as 
‘‘q stimulus,”’ whilst a slicing cut, removing a man’s 
ear and leaving a growth of scar tissue in its place, is 
also dismissed as ‘‘a stimulus,” it is obvious that 
two things profoundly different in character and im- 
portance are confused under a common heading. The 
first is the absolutely essential and widely distributed 
condition for the continued existence ef a living thing; 
the second is exceptional—an abrupt change with 
correspondingly exceptional result. Neither is cor- 
rectly described as ‘a stimulus,” though many 
stimuli of different nature occur in connection with 
both. 
Dr. Reid says he will admit that he is 
quibbling about the meaning of the term 
“acquired characters” if I will indicate how an 
inborn trait is more inborn and less acquired than 
an acquirement. The term ‘inborn trait” has 
nothing to do with the matter, as I have explained 
above. The words ‘‘change” and “acquire’’ imply 
an existing standard from which there is change or to 
which there is addition. The fact that the standard 
is itself an acquirement when viewed in relation to 
another phenomenon, namely, a reproductive germ, is 
irrelevant. 
Dr. Reid quotes passages from Wallace, Weismann, 
and Romanes which do not treat of the matter under 
discussion, and suggests that he “sins with them,” 
and that they agree with his forced interpretation of 
the term ‘‘acquired characters.” The suggestion 
seems to me to be devoid of justification. 
Chiefly, however, I object to Dr. Reid’s stating 
that I have called this ‘ta historical discussion,” 
implying that I attach historical importance to it. I 
have used no such words. This statement by Dr. 
Reid is erroneous, as is also his attribution to me of 
certain opinions about the muscular development of 
an ordinary individual and of a blacksmith. He says, 
“Sir Ray Lankester regards the former as normal 
and therefore inborn and inheritable, and the latter as 
abnormal and therefore acquired and non-inheritable.” 
This is entirely imaginary. I never wrote a word on 
the subject of muscular development, nor have I 
stated that abnormal qualities are necessarily acquired 
and non-inheritable, or anything of the kind. I do 
not desire to continue a discussion in which fictitious 
words and opinions are attributed to me. Nor do I 
NO. 2216, VOL. 89| 
desire to obtain any ‘‘admission” from Dr. Reid. 
1 am content to leave the matter to the judgment of 
your readers. 
April 5. E. Ray LANKESTER. 
Giouds and Shadows. 
On the evening of aster Monday 1 noticed in the ~ 
western sky an eifect which was unlike anything | had 
ever seen before. he sun was just setting behind a 
great bank ot cloud, the rest of the sky being tairly 
clear, except for a thin veil of alto-stratus (it was not 
very high), which was moving at a good rate from — 
the north-west, and stretched across the whole sky. 
This stratus was scarcely noticeable at first, as the 
sun’s rays shining through it produced a milky kind 
of light in the sky. In startling contrast to this 
there appeared about halfway between the horizon 
and the zenith, to the south-west, what looked like 
an extraordinary ‘cloud,’ which compelled attention. 
It was obvious, however, that this was no cloud, as 
it remained quite stationary, while the stratus (which 
I now observed) and also a few small lower clouds _ 
were driven quickly across the sky. : 
I became greatly interested in the phenomenon, 
and watched it closely for half an hour or more, and 
the impression I got was that the apparent cloud 
was really a heavy shadow, cast upon the otherwise 
brightly illumined stratus by some unseen object 
away in the west, which was intercepting the sun’s 
rays. The ‘dark patch’ varied in shape and size, | 
expanding and contracting, but preserving on the | 
whole a shape somewhat like a fan, and keeping the 
same position in the sky. 
Atter a time I noticed an exactly similar effect — 
growing into shape, halfway between the first one 
and the point where the sun had set, so that a line 
drawn through them from the sun would be at an — 
angle of about 45° with the horizon. 
I made notes and rough sketches at the time, and 
could give more complete details as to the conditions 
existing, and the varying shapes and positions of 
the dark ‘“‘shadows.” It may be that this effect is — 
not uncommon, and is easily accounted for; but _ 
although I have studied the skies for many years” 
1 have never before seen anything like it, and I 
feel confident that it must have been, at any rate, 
unusual. ‘ - 
While freely confessing ignorance of any scientific 
knowledge on such matters, I should be very 
glad to be enlightened as to the explanation of © 
the phenomenon, and also to hear whether anyone 
else noticed the occurrence. 
Cuas. TILDEN SMITH. 
“Chisbury,”” Little Bedwyn, Wilts, April 15. 
Winter in India. 
I notice that in Nature of February 15 your re- 
viewer quotes without comment a_ passage from 
“Freshwater Sponges, Hydroids and Polyzoa”’ (Fauna 
of British India Series) which implies that winter in 
coolest. This must be a slip on the part of the author. — 
Not only is there a considerable quantity of water” 
in rivers, tanks, and pools in winter compared with 
the spring and early summer, but the relative humidity 
is very much higher. In cases where I have collected 
figures the mean relative humidity is at about the 
average of the whole year in December and January, 
and then drops continually up to the first half of 
May, but it would doubtless vary in different parts 
of the country. inls Jals del: 
Camp, Central Provinces. 
India is the driest time of the year as well as the | 
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