These incubators are each regulated at various temperatures, and are employed for observing the growth of parasitic fungi and bacteria under artificial conditions.

The assistant's laboratory is situated at the extremity of the east. wing, and is well lighted on three sides. A blackened wooden laboratory bench runs round on the sides opposite the windows (figs. 2 and 3). The room measures 23 feet 11 inches by 13 feet. Adjoining it is a small room facing south, measuring 12 feet 3 inches by 6 feet. 5 inches, which is heated by electricity and is used as an incubator in the cultivation of organisms on a large scale.

Facing north are two rooms 18 feet 1 inch by 13 feet 6 inches and 13 feet by 12 feet 3 inches respectively. These are fitted up as research rooms, the smaller room of which can also be used as a darkroom for photographic purposes. Also facing north is the general office for the clerical staff, measuring 18 feet 1 inch by 13 feet 6 inches.

The sterilizing-room and general laboratory is situated in the north-west corner, and measures 18 feet 1 inch by 11 feet 4 inches. To it a small washing-up room 8 feet 4 inches by 7 feet 7 inches is attached.

Next to the sterilizing-room, also facing north, is a room 18 feet 1 inch by 7 feet which is provided with a cellar. This is used for the storage of culture media, etc.

The main entrance opens into a large central hallway, on the walls of which are hung photographs and illustrations of various plant diseases and of edible and poisonous fungi. (Fig. 4.)

All the incubators, sterilizers, autoclaves, paraffin baths, and other necessary appliances are heated by electricity. The only naked flames used in the laboratory are spirit lamps for the purpose of sterilizing platinum needles, etc.

Having now described the phytopathological laboratory of the Union, it will be well perhaps to say a few words regarding the nature of the work that is being conducted there.

The laboratory has been established for the purpose of giving farmers and fruit growers, and those interested in any way in the agricultural industry of the country, information regarding diseases in plants and insects caused by fungi and bacteria, information regarding edible and poisonous fungi, and information with respect to remedial measures against parasitic and non-parasitic diseases of plants, including the action and use of fungicides. Any one desirous of information on these points should always, if possible, forward specimens for examination, and state as fully as they can in the case of diseased plants their own observations as regards the general appearance and effect of the disease, the percentage of the crop affected, and any further information that is deemed of interest.

In forwarding diseased plants for examination the material. should always be well wrapped up in plenty of dry newspaper and dispatched so that it will arrive at the laboratory in as fresh a condition as possible. It frequently happens that specimens are either sent loose in a large cardboard box or wrapped up in a damp cloth. In the first case the specimens usually dry up too quickly, and in the second case they often become far too mouldy before they reach their destination. Specimens for examination should be addressed to "The Chief, Division of Plant Pathology and Mycology, P.O. Box 1294, Pretoria," and marked "Diseased plants for examination."

Farmers and planters who contemplate planting out crops of any kind on a large scale are also advised to consult the Division before doing so as to the dangers of infection from the various fungus pests and bacterial diseases that are likely to be encountered. For it has happened more than once during the past few years that considerable sums of money have been thrown away in attempting to raise crops under conditions which the Division at the outset would have predicted to have been mere folly.

It is also most important to remember that in dealing with plant diseases prompt action is very necessary, and that it is only by an intelligent appreciation of the causes of the disease that the trouble can be remedied or mitigated. It is no use waiting until the crop

has been partially or completely destroyed before any steps are taken to cope with the disease, as the damage once done cannot usually be repaired. As soon as any symptoms of disease are noted specimens should be forwarded for examination and report. It is well to remember that the whole principle of treating plant diseases rests on methods devised for the prevention of disease rather than the treatment of plants when once affected, and in no other connection can the proverb Prevention is better than cure" be said to be more applicable than in the treatment of plant diseases.

In addition to work of this kind, which may be termed the ordinary routine work of the laboratory, the scientific staff is engaged in research dealing with the investigation of new diseases peculiar to

the country. For instance, Miss Doidge, M.A., F.L.S., has almost completed a study of a bacterial disease of mangoes prevalent in the Transvaal and Natal, while Mr. P. A. van der Byl, M.A., is busy with investigations dealing with the gumming of wattles, a red spot in cheese, and a black spot in butter, the two latter being caused by fungi.

The cultivation on a fairly large scale of a fungus which is parasitic on bagworms in the wattle plantations of Natal has been carried out in the laboratory, and some hundreds of cultures will be ready for distribution in September to a limited number of growers who have assisted in the work by supplying sacks of the insects as food material on which the fungus has been grown.

Another important and most necessary function performed by the Division is that of keeping itself up to date and informed in regard to plant diseases prevalent in other parts of the world, and of advising. the Government as to what steps should be taken to prevent the introduction and spread of such pests into South Africa.

A special study is also being made of the fungi parasitic on the native plants and grasses and their inter-relationships to the introduced plants and crops. This comprises a study of the fungus flora of South Africa, and forms the greater part of the material stored in the herbarium alluded to above.

Specimens of fungi on native trees, shrubs, and other plants will always be gladly received from any correspondents who care to send such material to the laboratory.

Recent Soil Investigation in the Cape Province.

By Dr. C. F. JURITZ, M.A., F.I.C., Chief Chemist, Cape Province. (Continued from page 345.)

OUDTSHOORN.

THE Soils Nos. 182 to 186 represent an area on the Kansa Flats, which it had been proposed to bring under irrigation. The Director of Irrigation had previously been struck by the presence of hardpan close to the surface, and, knowing the effect of this impermeable formation in other parts of the division, he had been very doubtful as to whether under the circumstances any portion of these flats was worth irrigating. Samples Nos. 182 to 185 represent the surface twelve inches of soil from different parts of the flats, and sample No. 186 was representative of the sub-soil of No. 183, the layer represented being taken at a depth of from 36 to 42 inches. In all, sixteen samples were collected from the four localities mentioned, but only

the five above referred to were subjected to actual analysis. All the sub-soils were very similar, consisting of hard "dorbank" or hardpan. This hardpan appears to have been formed by the cementing together of the particles of soil by means of iron oxide and hydrate, in much the same manner as bog-iron ore is formed. No. 186, one of these sub-soils, contained also a large amount of carbonate of lime, and an appreciable amount of magnesia. The other sub-soils were, on the whole, free from lime. Even in the surface sample No. 182 a considerable quantity of "dorbank" (hardpan) was found, and in no case was the soil proper more than one foot deep. Soil in this condition would obviously be unsuitable for crops that require greater than twelve inches depth of soil. more especially where, in consequence of the ground being level, the tendency would be to become waterlogged.

Samples Nos. 187 and 188 were taken on the farm Vlakte Plaats in such a manner as to represent respectively the soils numbered 18 and 19 in the table on page 98 of my "Agricultural Soils of Cape Colony," an interval of eleven years having elapsed between the collection of the two sets of samples. As far as possible No. 187 represents the same soil that No. 18 represented, and No. 188 that of which No. 19 was a type. No. 187 is considered to be typical of the soil from the valleys amongst the mountains, and is described as a very rich virgin soil capable of producing magnificent potatoes, but after some years of cultivation decreasing in productiveness. No. 188 represented a virgin soil of Karoo type, very good for most crops except potatoes. Both samples were collected so as to represent the soil profile from the surface down to a depth of 12 inches. No. 187 was a dark, yellowishbrown soil apparently somewhat clayey. No. 188 was slightly lighter in colour, and had the texture of a good loam. The results of the usual agricultural chemical analyses were as follows:

The percentages of certain water-soluble constituents of these soils were determined with the following results:

These percentages of alkali salts cannot be considered excessive. It appears that only the sub-soil No. 186 shows any considerable indications of brack, and that the six surface soils do not contain alkali in injurious amounts.

Partial mechanical analyses of the six surface soils resulted as follows:

grains.

Quartz and fine-grained quartzite.

As above remarked, the physical disadvantages of the Kansa Flats soils arise from the presence of the hardpan. In plant food content they are rather poor, being derived from the sandstones of the Uitenhage series which extend between the town of Oudtshoorn and Calitzdorp. Hence they do not exhibit the remarkable richness in plant food that is characteristic of so many of the Oudtshoorn soils; their resemblance is rather to the soils Nos. 3 and 14 (from Hazenjacht and the vicinity of Buffels Vlei) of the soils tabulated on page 98 of Agricultural Soils of Cape Colony." Their percentages of nitrogen, potash, and phosphoric oxide may be described as middling, and in their lime content all the Kansa samples are remarkably poor. The plant food supply of the two Vlakte Plaats soils is far better, although in No. 187 there is a drop in the phosphoric oxide. It is most probable that the deterioration of the soil which is referred to above is due to the exhaustion of phosphoric oxide, and probably also of potash. The amounts of lime, magnesia, and nitrogen in these two soils are particularly high; in fact, both physically and chemically, the soils appear to be of fine quality and should give splendid results if the supply of plant food is not allowed to be depleted, but is continually replenished as fast as it is used up by the crops.