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206 ELEVATED TEMPERATURE OF THE MALE INFLORESCENCE OF CTCADS. 
ON THE ELEVATED TEMPEEATURE OE THE MALE INELOEESCENCE OE 
CYCADEOTJS PLANTS.* 
By Dr. DE VEIESE, Professor of Botany in the University of Leyden. 
Jj>l LL living bodies have a temperature peculiar to themselves ; that is to say, they have a temperature, 
AA different from and independent of those which surround them. This temperature is intimately 
connected with their nature, and is modified according to the nature of the different conditions in 
which they may he. 
This necessary consequence of the successive changes which organic matter undergoes during 
life, is in its turn one of the causes which preserve organised bodies, and by which animal and vege- 
table life are protected from destruction or dissolution, which external circumstances would not be 
long in producing. It is this peculiar temperature which permits animals to inhabit regions of the 
globe that, on account of their cold, would he uninhabitable ; which allows the developement of aquatic 
vegetables in frozen water; which defends trees against winter; and which, in tropical regions, 
causes vegetables to withstand a temperature often too high for their organisation. 
The observations upon the elevated temperature in the flowers of Aroideous plants in general, have 
shown that this phenomenon takes place in a high degree, and originates in a sort of combustion, 
that is to say, an absorption of oxygen and emission of carbonic acid. Very recently a high degree 
of temperature has been observed in a plant belonging to a family in which that phenomenon has not 
been noticed before. Mr. Teysman, chief gardener at Burteuzorg (in Java) in 1845, has informed me 
that he has observed an elevated temperature, and at the same time a very strong smell, in the male 
cone of Cycas cireinalis. I received from him, in October 1849, and November 1850, seven series of 
observations, made in the aforesaid garden upon male flowers of this plant. What is most remarkable 
in these observations is connected with the following facts : — The elevation of the temperature always 
takes place between six and ten o'clock in the evening. Messrs. Bory (at the Isle of France) and 
Hasskarl (at Java) have observed the maximum at six o'clock in the morning ; De Saussure observed 
it in the Arum italicum between four and seven in the evening ; and the Colocasia odorata, in the 
gardens of Paris, Amsterdam, and Leyden, has always attained its maximum at noon. This periodical 
production of heat differing in different climates, and in flowers of different families, has not yet been 
accounted for. It appears from the inspection of the tables of several hundreds of observations, that 
the maximum has varied between 9° and 14° Cent., and the difference has been 3 - 75 — 4 - 50°. 
It is acknowledged that in general, the coloured parts among the appendicular organs, in vegetables 
have an absorption and exhalation contrary to those of green plants. The oxygen is absorbed, 
carbonic acid is exhaled. Both take place in organs where the elevated temperature is shown in a 
high degree. It is proved that this phenomenon is constantly preceded and accompanied by rapid 
growth in the flower. Nothing prevents us from admitting that the same action actually takes place 
in the male cone of Cycas, where the rapid developement of pollen, or the formation of cells which 
compose it, should surpass all that has been observed in this respect in the vegetable kingdom. We 
shall endeavour to prove it by the following calculations : — The male cone, of which I have given the 
description elsewhere, is (in metres) 0.450 long, and 0.200 broad. The sum of the external surface is 
difficult to estimate, on account of the irregular form of the organ, but it cannot be considerable. In 
calculating the number of scales at 3500, and the surface of each of them at four square centimetres, 
the whole sum of the organs which compose the cone should be equal to 14,000 square centimetres. 
The surface of the scales at the under-side is covered with unilocular anthers almost contiguous, and the 
number of these anthers may be calculated at 400. Thus the total number of these anthers might be 
calculated at 1,400,000. Each anther contains several thousands of granules of pollen, which in a 
very short space of time undergo, in their cavities, all the necessary organic, physical, and chemical 
changes. 
It is easy to admit that the alternate absorption and emission of gas, in so rapid a process, 
must play an important part. The whole leads us to believe that in cases where there is so great an 
analogy in the functions (as in the flowers of Aroideous and Cycadeous plants), the same agents should 
regulate and preside over the phenomena of life, of which all that modern science has been able to 
discover, as to its mode of action, belongs to physics and chemistry. 
* From Hooker's Journal of Botamt. 
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