THE 44 SPOT ” ON PELARGONIUMS. 
45 
of excessive heat and dull weather, occasioning much trouble 
to the plant-grower. My plants were in a vigorous condition 
towards the close of the autumn, but shortly after exhibited 
an unhealthy aspect, followed by unequivocal symptoms of 
4 spot,’ which continued throughout the growing season. I 
attribute the disease to the sudden reversion of atmospheric 
influences (changing from bright to gloomy) acting upon the 
elaborative organs of the plants in the manner of a check, so 
as probably to cause a disruption of some of them. I am not 
quite prepared to say it is infectious, but strongly suspect it. 
“ C. C.” 
G. writes thus: — “ My opinion of the 4 spot’ is that it is 
caused by the chilling effects of a fluctuating atmosphere; the 
plants being excited to the utmost one day, and perhaps the 
next subject to precisely the reverse. It is only to be ob¬ 
viated by endeavouring to preserve an even temperature in the 
house, not that it is to be regulated entirely by the thermo¬ 
meter ; for it is of less consequence to maintain at all times 
the same degree of heat than to have a more regular amount 
of moisture present in the atmosphere in which the plants are 
growing.” 
Another correspondent, Mr. Wilson, says, he believes 44 the 
4 spot’ on Pelargoniums to originate in this way. The plants,* 
in all probability, about the end of September, or even a 
week or two later, are making an abundance of new foliage, 
in fact, are in very active growth, and the possessor is flattering 
himself that his plants will 4 look well ’ through the winter, and 
thus encourages them to a continuance of this growth, without 
at all thinking of the necessity of getting the new parts matured 
and hardened; the fine weather of the season all the time urging 
the plants forward, until at last the dull cold weather of No¬ 
vember overtakes them in a green succulent state; their vessels 
are full of crude undigested sap, which they are unable to disgorge 
from want of sunlight, and it necessarily becomes stagnant and 
putrid, breaking through the epidermis like a cutaneous disease. 
Nearly the same result will follow’ an overdose of food at any 
season, accompanied by a reduction of light or temperature — 
as may be proved by experimenting on a worthless plant at 
any time.” 
All these opinions seem to coincide in the importance of 
attaining a proper maturity for the grow'th of the preceding 
f 3 
