BIOLOGY. 329 



sible to the external air, but also deep in the tissues of living 

 things, being carried inwards bodily by tlie growing tissues, in 

 the same way that particles of charcoal get into the interior of the 

 intestinal vessels running to the liver. In ordinary "ring-worm," 

 the fungi which are the cause of the disease, according toDr. Fox, 

 get into the hair follicle, reach the root, and are carried up b}' the 

 growing shaft into the body of the hair. In like way, rusts eifect 

 an entrance within the leaves of grown-up plants, but at a very 

 early date, through the first cotyledonous leaves. We are led to 

 suppose that the entrance of mildews and rusts is oftentimes at a 

 very early date, and that the germs lie dormant, often for a long 

 time, till the favorable opportunity arrives for their development. 

 Fungi never appear to flourish on healthy surfaces, but always 

 on those which belong to devitalized beings, and only constitute 

 disease when they are developed to an excessive amount. The 

 author entered into the question of the polymorphism of fungi, and 

 the efl'ects they produce in disease, showing that these are chemi- 

 ical, mechanical, and vital. After spealiing especially of ring- 

 worm, he concluded — and this is the interesting point in reference 

 to the "blue mist" — that the prevalence in undue amount of 

 microscopic fungi is always coincident with tliat of epidemic dis- 

 eases ; that the two could not be regarded as cause and eflect, but 

 were both helped out by the same influence. Whatever debilitates 

 nian renders him more liable to epidefnic disease, and whatever 

 induces an unhealtliy state of vegetation favors the rapid devel- 

 opment upon it of fungi such as constitute rusts, moulds, and 

 mildews ; but these do not seem to be capalile of producing any- 

 thing like epidemic poison, which is probably not vegetable in 

 nature. The existence, then, of the " blue mist," supposing it to 

 be due to vegetable germs, can only be looked upon as a coinci- 

 dence as far as cholei'a is concerned. — Reader, 1866. 



IN WHAT PARTS OF PLANTS THE POTASH RESIDES. 



On this subject some curious chemico-agricultural inquiries have 

 recently been reported to the French Academy by Mr. Isidore 

 Pierre. The object of this savant's researches was to discover 

 in what parts of cereal plants, and during what seasons, potash is 

 most abundant. In carrying out his investigations, the greatest 

 care was taken to insure the examination of the corresponding 

 parts of several specimens of corn. The plants were analyzed 

 before flowering, in bloom, and in the fruit-time. From a great 

 numl^er of experiments the author draws the following conclusions : 

 1. That in the various parts of the plant (leaves, nodes, and inter- 

 nodes), the proportion of potash increases in a well-marked man- 

 ner as we pass from the lower to the upper parts. 2. That in 

 parts of the same name and position this proportion tends to 

 diminish as the plant advances towards the period of ripening. 

 Sometimes this diminution is much less marked in the leaves than 

 in the nodes and internodes. It seems tliat potash salts play a 

 more important part in the life of plants than soda salts ; in fact, it 

 is seen that the former predominate in those parts, while soda is 

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