43 
since expressed their regrets that they did not do so. By each of 
the candidates about 80 per cent. of the questions were very satis- 
factorily answered, and diplomas were issued to them. 
Mr. Henry Kraemer, who conducted the course in Microscopi- 
cal Botany, reports that his class contained seven members and 
that ten lessons were given. An oral examination was conducted 
and four members were awarded diplomas. 
Miss Effie A. Southworth read a paper entitled « A Review of 
the Nitrogen Question.” Following an enumeration of the forms 
in which nitrogen was offered to the plant was a review of the 
early work by Boussingault and others, leading to the conclusion 
that free nitrogen was not available as plant food. Offered to the 
roots, plants prefer nitrates to ammonia salts. An examina- 
tion of leguminous plants showed that they possessed peculiar 
qualities of absorbing nitrogen. This led to an examination of 
the tubercles found on their roots. “After a review of the different 
theories concerning the nature and function of these tubercles it 
was stated as the present accepted notion that they are caused by 
infection by a fungus, and have some connection with the nitrogen 
producing qualities of the plants, that is, by symbiosis with the 
fungus the macrosymbiant can make use of more nitrogen than it 
otherwise could. This work on the tubercle was followed by a 
new investigation of the sources of nitrogen for plants in general. 
Dr. B. Frank has especially worked upon this subject, and come 
to the conclusion that all plants absorb the free nitrogen of the 
air, and that the early stage of growth before the full development 
of the foliage, in the time when nitrates are especially required, 
free nitrogen assimilation becoming established when full foliage 
appears. : 
The paper was discussed by Dr. Curtiss and Prof. Rusby, who 
pointed out that even if it were proven that all plants absorbed 
free nitrogen, it could not be that they would at any period be- 
come independent of nitrates, as the fertilization of crops by 
nitrates in all stages of growth was productive of good results. 
Mr. T. H. Kearney, Jr., read a “ Report on the Botanical Ex- 
ploration of Southeastern Kentucky in 1893,” illustrated by speci- _ 
mens. The colleetions included 323 species made in six weeks of 
August and September, six being new to Gray’s Manual region, : 
with one variety and probably one species new to science. be a ie 
