46 
in relation to the occurrence of diseases which have a direct 
dependence upon season, as also those which at intervals are 
epidemic, have of late years attracted a little of that attention 
which the subject merits, and will, doubtless, hereafter receive. 
When, in our investigations, we, to a greater extent than has 
hither been done, look upon organic nature as constituting 
one great unity, the phenomena of one division as having a 
relation to those of other divisiohs of that unity, and all alike 
influenced by surrounding conditions, then may we expect 
that greater results than have heretofore followed our inquiries 
shall be attained. 
25. Here, in our own country, the relation of aphidae and 
other insect pests to season, and to particular seasons, is suffi- 
ciently and unpleasantly familiar. No reference to thermometer, 
or barometer, is needed to indicate what our own senses tell us 
is weather in which blights appear in gardens and orchards. 
The circumstance has recently been recorded that the appear- 
ance of the Thrifts cereale takes place in connexion, as regards 
time, with the recurrence of electric disturbances of the 
atmosphere; hence the popular name “ thunder blight” given 
to that creature.* Among other circumstances for which no 
precise and definite cause has been discovered, are the process 
by, and manner in, which species and genera of such “ pests” 
as are alluded to succeed each other. Having appeared, their 
recurrence has reference to season. But how about their first 
development in myriads ? There is no reply. 
26. The relation of diseases in animals to season obtains 
confirmation by what, unfortunately for those concerned, and 
for their owners, has in this country come to be nearly the 
usual state of things. Here is a recent illustration. In 
Norfolk the disease among cattle, known as splenic apoplexy, 
first made its appearance on July 12, 1874; on the second 
occasion of its prevalence, the date of its first attack was 
June 19, 1877; that of its third appearance June 10, 1880. 
To what special conditions this comparative uniformity in 
the recurrence of anthrax refers, we have no sufficient data 
to show. Possibly — so runs the articlef quoted from — “in 
this direction meteorological science, aided by topographical 
considerations, may sooner or later afford us a clue to the 
solution of the question.” It is added: “ As in 1874 and 
1877, so in 1880, the primary source of infection cannot be 
urged alone as the centre from which the more general out- 
break sprung.” 
* Hardwick’s Science Gossip, October, 1881, p. 224. 
+ Journal of the Royal Agricultural Society of England, Vol. VH., 1881. 
Part 1., p. 50. 
