Bulletin Volume 141, PT. 5 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...raw-potato cylinders prepared as described later. Bacterial contaminations often occur which necessitate several further transfers for their elimination, and this is made easier by the use of the bean-agar medium described later. VARIOUS CULTURE MEDIA TESTED. In the course of these studies a wide variety of culture media has been tested. Some of these media proved more or less favorable for the growth of Phytophthora, while others were entirely unsuited. Normal growth and fruiting have been obtained on raw-potato and pumpkin blocks, potato gelatin, and Lima-bean agar. On certain other media, such as pumpkin agar, pumpkin gelatin, and some of the synthetic media, there was some growth, with few or no conidia, while on many others no growth was apparent. In considering the details as to the behavior on these media it will prove helpful to group them as follows: (1) Raw and cooked vegetables; (2) vegetable broths, either alone or with gelatin or agar; (3) synthetic liquid media; (4) synthetic media with agar or gelatin; (5) synthetic liquid media and silicate jelly. All cultures were carried at 18 to 20 C. unless otherwise specified. GROWTH ON VEGETABLE TISSUES. The media tested in these trials included raw or living potato tubers, raw muskmelon and pumpkin rinds, parsnip roots, and also cooked tissues from different parts of the potato and pumpkin. The raw potatoes were prepared as follows: Medium-sized sound tubers were washed, immersed 10 minutes in a 0.1 per cent solution of mercuric chlorid to disinfect, the surface layer was cut away with a knife kept sterile by repeated naming, and blocks about 1 by 1 by i centimeters in size were cut from the interior. Each such block was then dropped into a sterile culture tube which contained about 1 cubic centimeter...