226 



SCIENCE 



[N. S. Vol. LII. No. 1340 



an opening of about 2 microns in diameter. 

 There are usually four or five tubes in large 

 sporangia and one tube in small siwrangia. 

 The zoospores are somewhat ovoid in form, 

 4 to 8 microns in length and very flexible. 

 The single cilium, 30 to 50 microns in length, 

 is attached at the broader posterior end and 

 trails behind when the spore is actively swim- 

 ming. There is usually one bright eyespot, 

 but there may be two. Conjugation of zoos- 

 pores has not been seen in my cidtures. 



Within twelve hours after leaving the 

 sporangia most of the zoospores settle down 

 at the margin of the hanging drop and be- 

 come rounded in form. A single germ tube 

 develops and grows out from the edge of the 

 drop and along the surface of the cover glass. 

 If the spore has come to rest too far from the 

 margin, the mycelium grows downward and 

 projects from the drop of water. The tube 

 may reach a length of 10 to 20 microns in 24 

 hours after the zoospore has left the spor- 

 angium. The mycelium usually branches 

 freely and irregularly after it reaches a length 

 of about 10 microns. In cultures 9 days old 

 the myceliiun averaged about 20 microns in 

 length. It varied from 10 to 60 microns 

 (total length of branches). 



Old galls are likely to contain nematodes, 

 Paramcecium and other ciliate protozoa, 

 several kinds of flagellates and amoeboid 

 protozoa. Some of these feed on the zoospores, 

 as many as 30 having been counted in a single 

 Paramcecium. Cultures free from these or- 

 ganisms were obtained by transferring ripe 

 sporangia, by means of a mechanically 

 operated micropipette, into hanging drops of 

 water. The zoospores escaped from the spor- 

 angia and sent out germ tubes in these 

 cultures. 



Much difficulty was encountered in finding 

 galls with spores that would germinate. Even 

 in such galls, only a very small percentage of 

 the resting spores germinated. In some cases 

 the zoospores escaped when the hyaline wall 

 was extruded only slightly through the fissure 

 in the brown wall. Usually the sporangium 

 became entirely free before the spores were 

 released. 



Hanging drop cultures of spores from 

 several galls produced sporangia for about 

 two weeks. Attempts to hasten the release 

 of zoospores by keeping these cultures on ice 

 over night were not successful. Cultures con- 

 taining sporangia were allowed to become 

 partially dry for a few minutes and then 

 moistened again. This effected the escape of 

 zoospores from ripe sporangia. It did not 

 change sporangia appreciably in which the 

 contents had not become differentiated into 

 spores. 



Germination was obtained in November 

 (1906) and in March, April, May, June and 

 July (1920). 



C. Emlen Scott 



Botanical Laboratory, 

 Stanford Universitt, 

 California 



SCIENTIFIC BOOKS 



Hand-List of Scientific Manuscripts in the 

 British Isles dating from "before the Six- 

 teenth Century. By Dorothea Waley 

 Singer. London, De La More Press, 1919. 

 8o. 12 pp. 

 Survey of Medical Manuscripts in the British 

 Isles dating from iefore the Sixteenth 

 Century. By Dorothea Waley Singer. 

 London, J. Bale, Sons & Danielsson, Ltd., 

 1920, So, 12 pp. 



These are important contributions to the 

 early history of medieval medicine and sci- 

 ence, the first fruits of a catalogue of some 

 30,000 scientific manuscripts of the Middle 

 Ages, found in Britain, and now in prepara- 

 tion by Dr. Singer and his wife. The value 

 of such a catalogue to future students will be 

 incalculable, going forward as it does simul- 

 taneously with the cataloguing and intensive 

 study of the scientific and medical incu- 

 nabula. As the social and scientific history 

 of modern medicine is to be found largely in 

 the files of medical periodicals of the eigh- 

 teenth to the twentieth centuries, so the un- 

 written history of medieval science is con- 

 tained in the manuscripts, the pathway to 

 which lies through the early printed books. 



