SCIENTIFIC SUMMARY. 
195 
BOTANY AND VEGETABLE PHYSIOLOGY. 
Hybrid Fruit of Orange and Citron. — M. Oudemans has observed a fruit 
half orange and half citron. Externally it had precisely the form and colour 
of a citron. Internally, four of the compartments presented the colour and 
taste of the flesh of a citron ; the other five had the qualities of that of an 
orange. The formation of this fruit may be explained in two ways. The 
tree which produced it may have been a hybrid between Citrus medica and 
C. aurantium. Or the flower which produced the fruit may have belonged 
to one of the above species, and have been fecundated, at least partially, by 
pollen of the other. On the first supposition the case would be parallel to 
that of Cytisus Adami. On the second, which M. Oudemans regards as 
most probable, we should have a fresh instance of the influence of the pollen 
on the fruit. — Les Mondes, December 14, 1876. 
History of Polyphagus Euglence. — Dr. L. Nowakowski has published (in 
Cohn’s “Beitriige zur Biologie der Pflanzen,’’ Heft 2, 1876) a most in- 
teresting and important memoir upon the history of this curious microscopic 
vegetable parasite, a member of the group of Chytridia, the true position 
and nature of which have always been somewhat doubtful matters. Most 
of them are parasitic upon other aquatic plants, generally adhering to the 
surface of their component cells and sending processes into the interior. 
The Polyphagus , however, devotes its attention to those well-known flagel- 
late infusoria, the Euglence , which it attacks when they are in the helpless, 
resting stage of their existence. The spores of the parasite are furnished 
with a variable number, four or more, of delicate, radiating filaments, one 
of which coming into contact with a Euglena, at once pierces its integu- 
ment and penetrates into the contained protoplasmic mass. It then rapidly 
increases in size, and usually emits other filaments which stretch out in 
search of more victims, whilst the body of the spore also increases in pro- 
portion to the success of its rootlike processes, and in course of time 
becomes a “pro-sporangium.” From this a sort of vesicle is pushed out, 
which after a time becomes a zoosporangium, and from it a cloud of zoo- 
spores finally escapes. Dr. Nowakowski has observed a true process of 
reproduction in these curious parasites. He finds that the individuals pre- 
sent two forms — one large, and generally spherical, which is the female 
plant j the other smaller, and more or less club-shaped, which is the male. 
These two forms conjugate in the following fashion : — The contents of the 
female plant project through an opening in its cell-wall and form an oval 
mass, with which one of the processes of a neighbouring male plant comes 
into contact, when the contents of the two mingle and a zygospore is pro- 
duced, from which a zoosporangium is developed, and this gives issue to a 
swarm of zoospores. From his investigations the author is inclined to refer 
the Chytridia to the Siphomycetes. 
CHEMISTRY. 
Phosphorescent Organic Bodies . — M. B. Radziszewski has lately published 
in the “ Reports of the German Chemical Society ” (1877, p. 70), a memoir 
