234 



NATURE 



\7uly 22, 1875 



has a large mineralogical collection and a nice chemical 

 laboratory, in which he makes his analyses. 



Let us now turn from what the Siamese have done for 

 science to what they are going to do. 



The King has instructed Dr. Gowan to erect an obser- 

 vatory in which regular barometric and thermometric 

 measurements are to be made. The rainfall and the 

 tides will also form a subject of measurements. Other 

 instruments will be added in time. As the Siamese have 

 a great fancy for photography, we shall perhaps soon 

 see regular photographs of the sun taken in Bangkok. 

 Various spectroscopes and telescopes are at the present 

 moment on their way out from England. It is also 

 intended to build a chemical laboratory in the palace. 

 The King's bodyguard are being instructed by Mr. 

 Alabaster in taking surveys. At the moment I write this, 

 they are out on a surveying expedition. 



All this shows that the inhabitants of Siam have a great 

 fancy for science, if it does not show more. Strong hking 

 for a subject is generally accompanied with, if not caused 

 by, the ability to deal with it and to overcome its difficulties. 

 Let us hope that some of the Siamese will take up their 

 favourite subject, not as amateurs merely, but with all the 

 seriousness of a profession. Many of them visit Europe 

 for several years. If some of these were to go through a 

 course of science, the knowledge thus gained, added to 

 their natural intelligence and love of science, would soon 

 make them good observers and able experimenters. 



In the meantime it will be interesting to watch the 

 growth and development of a country in which science is 

 the recognised and favourite study. English men of 

 science cannot refuse their sympathy to a king who, under 

 great difficulties, does his best to improve his country, 

 and who readily accords to science the position which 

 they are striving to obtain for it in their own land. 



Arthur Schuster 



THE RESTING-SPORES OF 

 FUNGUS 



THE POTATO 



"P OR some reason unknown to me (but probably owing 

 -*■ to meteorological conditions pertaining to this season 

 or the last) the potato fungus began its ravages this sum- 

 mer a month or six weeks earlier than usual. It not only 

 appeared out of season, but it came in a different form 

 from anything within the memory of the younger bota- 

 nists of the present generation. It is considered probable 

 that the present condition of the disease is similar with 

 that long ago known as " the curl," a pest known a con- 

 siderable time before Peronospsra infestans, Mont., was 

 described as European. 



At the beginning of June I had potato-leaves sent to 

 me for examination from the office of the Journal of 

 Ho7-ticulture ; these leaves were badly diseased, spotted 

 and foetid, and from certain •f the stomata a few threads 

 of the Pero7wspora were emerging ; this fact, from the 

 unusually early appearance of the fungus, I made a 

 special note of. 



On June 16 Mr, Berkeley brought leaves sent to him 

 for examination by Mr. Andrew Murray, (which were 

 spotted in an exactly similar manner with mine), to the 

 meeting of the Royal Horticultural Society. At the 

 same time Mr. Berkeley exhibited a sketch of two rather 

 large nodu»lose (or reticulated) bodies found by him within 

 these leaves, as a possible species of Proiomyces, but 

 since then known to be the resting-spores of Peroiwspora 

 infestans, Mont., here illustrated. 



The presence of these warted bodies in the leaves, a« seen 

 by Mr. Berkeley, led me to make a searching examination 

 of the Chiswick plants then greatly suffering from the pest, 

 and I at once found similar bodies very sparingly diffused 

 amongst the tissues of the leaves, with a few branches of 

 Peroiwspora and threads of mycelium, and two semi- 

 transparent bodies of different sizes which were new to 

 me. On attempting to disengage these presumed speci- 



mens of Protomyccs from the black, hard, and corroded 

 spots on the leaves by maceration in water, I found the 

 continued moisture greatly excited the growth of the 

 mycelium. After the lapse of a week the threads bore 

 (amongst the intercellular spaces of the leaves) the semi- 

 transparent bodies of two sizes which I had before seen 

 and measured, and which I now refer without doubt to 

 the oogonium and antheridium of the potato fungus. It 

 is very uncommon to find a fungus bearing sexual and 

 asexual fruit at the same period of growth, and in this 

 instance the old asexual fruit was very sparingly pro- 

 duced. I, however, afterwards found the fungus with 

 both forms of fruit and with ripe free resting-spores, 

 inside the cavities of the putrid stems, and I found the 

 ripe resting-spores and the sexual organs sometimes in 

 conjugation within the tissues of the potato tubers when 

 the substance was reduced by decomposition to the soft- 

 ness and semi-transparency of butter. 



By keeping the potato-plants closely under observation 

 from that time to this, a period of from six to seven weeks, 

 I have seen and figured these bodies in every stage of 

 growth, and have been able to preserve some of the best 

 material for future careful mounting. Those who may 

 care to know in detail how, from the slightest clue at first, 

 the subject was worked out to its present aspect may refer 

 to the Gardener's Chronicle for July 10, 17, and 24 last, 

 and to this week's Journal of Horti culture. 



Oogonium antheridium and mature resting spore of P eroiiospora in/esians , 

 fS^^ L-Moiit. ^ ^ 



The aiitheridia,oogonia, and oospores (or resting-spores) 

 in Peronospora infestans, Mont, are very similar, with the 

 same bodies in other species of Peronospora, in fact when 

 they are drawn to scale and placed side by side there is 

 very httle difference to be detected. The accompanying 

 illustration shows the oogonium (a) and antheridium (b) 

 in contact as taken from the tissues of the leaf. At c is 

 shown a semi-mature resting- spore with its fecundating 

 tube attached and its coat of cellulose accidentally pushed 

 aside by maceration in water, as taken from a putrid 

 potato-stem. At E is illustrated the perfectly mature 

 resting-spore, free from its coat of cellulose taken from a 

 tuber in the last stage of decomposition. At F is shown 

 the resting-spore of Peronospora arenarice, Berk, drawn 

 to exactly the same scale to show similarity in size and 

 conformation. The figures in the cut are uniformly en- 

 larged seven hundred diameters, and the mature oospore 

 or resting-spore measures on the average •00142 inch in 

 in length, and '001 14 inch in breadth. 



Worth iNGTON G. Smith 



