508 BOTANICAL GAZETTE [JUNE 
chaos in the taxonomy and morphology of this group, and the imperative need 
of a more stable system of nomenclature. A study of the life history of the 
Ascomycete to which they assign the name Pezizella lythri reveals the following 
facts. The life cycle includes three stages. The conidial stage has received 
at least seven generic and ten specific names; the pycnidial stage has been 
referred to at least four genera, and has had at least twelve specific names; 
while the ascogenous stage has been described but once so far as known. In 
one or another of its stages, this fungus has been found on about fifty different 
host plants, widely sg see throughout North America and Europe, and 
it also occurs in South America. With such a range of forms and hosts and 
geographical occurrence, it i is not surprising that names multiplied, but inten- 
sive studies of life histories will bring some order out of such confusion.—J.M.C. 
Rhus poisoning.—The nature of the poisonous principle in Rhus and the 
method of its transmission from plant to person has excited much controversy. 
There have been two main theories: (1) that the poison is volatile, and there- 
fore infection can take place without contact with the plant, and (2) that the 
poison is non-volatile, contact with the plant being necessary for infection. 
McNair” reports the results of experiments which lead him to conclude that 
the poisonous principle is non-volatile. Poisoning without contact with the 
plant can occur only by contact with something, such as clothing, shoes, etc., 
which has the poison on it, or from the smoke of the burning plants, the 
soot of which seems to carry the poison. He finds that the poisonous principle 
is confined exclusively to the resinous sap of the resin canals. The literature 
of the subject is well summarized, the work of Prarr, who concludes that the 
poison is a non-volatile skin irritant, being especially emphasized. PFAFF 
applies the name toxicondendrol oil to the poison.—S. V. Eaton 
Inhibition by metabolic products.—CHAMBERS®* finds that the hydrogen 
concentration of the culture medium is very important in cultures of 
Bacillu scoli, There is a slight checking of growth at Px 5.5, and an increasing 
intensity to lethal concentration between Ps 5.1 and 4.9. Inhibition begins 
on the alkaline end from Pu Ue ° and is , » depending upon age of culture and other 
factors. Pu 7.6i tory action with Py 5.1. Inan asparagin- 
CaCO; bouillon Px 9. 5 is not foal tn cultures with the hydrogen ion 
concentration controlled, the maximum count was 3,750,000,000 bacteria to 
the cubic centimeter, contrasting with 281,000,000 in dextrose bouillon with 
the hydrogen ion uncontrolled. ‘The inhibitory action of the metabolic 
products of dextrose other than the hydrogen ions is only evident near the 
critical acid concentration.” —WM. CROCKER. 
27 McNarr, James B., The transmission of Rhus poison from plant to person. 
Amer. Jour. Bot. 8:238-250. 1921. 
 Cuampers, W. H., Studies in the physiology of the fungi. XI. Bacterial 
inhibition by metabolic products. Ann. Mo. Bot. Gard. 7: 249-289. 1920. 
