24. Several of the phenomena of animal life present a 
distinct relation to meteorological conditions, and seasonal 
changes. This relation is, for the most part, more apparent 
as regards what are called the lower forms of life, than what 
are designated the higher. What, for example, are the 
ultimate causes which determine the abnormal profusion of 
insect, or even yet lower forms of life, in particular years 
and seasons, as compared with similar periods separated by 
intervals more or less long ? Except that the recurrence of 
such phenomena takes place during the same periods of the 
year, little, if anything, further transpires on the subject. 
Ova are deposited in myriads every year; but only at intervals, 
sometimes of several years, is full development attained.* 
Equally remarkable is the destruction which, at intervals, 
sweeps over and destroys entire races of animals. With regard 
to some forms in which that destruction happens, no relation 
to season or special locality has been determined. With 
regard to others, the occurrence of widespread mortality has 
a distinct connexion with seasonal and climatic diseases 
among plants and in the human species. In Sweden, for 
example, the occurrence of pests among flocks and herds at 
the commencement of the national celebration of the midnight 
sun — namely, about the first of May, is looked upon as a 
seasonal “ visitation,” only to be averted by sorceries. In 
India, the seasonal recurrence of what are called malarial 
diseases in man, is signalised by the prevalence of similar 
affections, not only among imported animals, but among those 
indigenous. In that country the phenomena of animal life. 
mere substitution of a word by another word matters little. We require not 
to revert to geological periods to observe in organic beings changes and modi- 
fications according to local conditions and circumstances in which those 
beings occur. To obtain practical confirmation of this fact, no scientific 
process of inquiry is necessary. Let us, for example, proceed to India by 
one of the ocean bridges which span the distance between England and her 
greatest dependency. Let us note, while en route, the conditions of physical 
geography, of meteorology, the characters presented by animated life, whether 
vegetable, animal, or human, and, at the end of our voyage, let us write to 
our friends at home and tell them whether or not, in the course of our passage 
we have observed as great differences in general, as numerous and striking 
modifications in type, as many instances confirmatory, if we so desire them to 
be, of “ evolution ” as are to be traced by comparing the remains found in a 
particular geological stratum in one region with those of similar or even 
different state in another region. Still more so is this the case if we continue 
our journey eastward to Australia and New Zealand. Again more so, if 
we return homewards, via America and the Antilles. 
* Here is an example. In October, 1881, locust eggs were collected at 
Nicosia alone at the rate of 20,000 okes, or 55,000 lb. per week. An oke 
contains on an average 13,500 eggs, so that the total gives 270,000,000 
locusts destroyed. 
