作者机构：
Frank Smart Student of Gonville and Caius College, Cambridge
摘要：
1. The effects of alterations in the reaction of the medium upon the various changes which succeed the initiation of development in the egg of Sphaerechinus granularis are described. It is concluded that the absence of a visible membrane in eggs fertilised in acid sea‐water is not a secondary result of any of the other known effects of acidity of the medium upon the sperm of the egg. 2. If eggs of Sphaerechinus are caused to develop without the formation of a normal fertilisation membrane by any of several methods, membranes cannot be formed by treatment with the usual parthenogenetic agents if more than three or four minutes have elapsed after the initiation of development. 3. If eggs in which development has been initiated in this way are placed in water containing small quantities of KCN before the appearance of the gelatinous layer (20–30 minutes after the initiation of development) and treated with sub‐ stances that form membranes in unfertilised eggs, typical membranes are formed. The suggestion is made that the KCN produces this effect by inhibiting the in‐ creased oxidations in the egg. 4. It is concluded that the substances which are responsible for the extrusion of the membrane remain unchanged in the surface of these eggs after the initiation of development and therefore play no part in the initiation of development. 5. Evidence is brought forward that treatment which can only be external to the egg, namely treatment for 10 secs, with sea‐water acidified to pH 4·4 by the addition of HCl, produces the initiation of development in a certain proportion of the eggs. It is concluded that the primary change in the initiation of development must consist of a change of the surface conditions of the egg, while in artificial parthenogenesis membrane‐formation is due to action of the parthenogenetic agent below the surface. 6. Evidence is brought forward to show that this primary surface change occurs in parthenogenetic activation when the eggs are placed into the solution containing the parthenogenetic agent and reasons are given why its effects do not appear in this solution.
期刊：
Journal of Economic Entomology,1923年16(2):161-168 ISSN：0022-0493
作者机构：
A. & M. College, Miss.
摘要：
Recommendations for fumigating nursery stock in the different states vary considerably in the strength of hydrocyanic acid gas to use and the time of exposure necessary. The variations in temperature and humidity throughout the United States would not permit of standard fumigation regulations for the entire country. It would seem desirable for the states in each section (for example, the Southern States) to adopt similar fumigation requirements for each kind of plant to be fumigated. Suggest further experiments to determine the fumigation schedule that could be adopted in each group of states in the country.
作者：
R.A. Houstoun Ph.D. D.Sc.;Eric W.M. Heddle M.A. B.Sc.
期刊：
The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science,1923年46(274):699-706
作者机构：
University of Glasgow<&wdkj&>Royal Technical College , Glasgow;[R.A. Houstoun Ph.D. D.Sc.] University of Glasgow;[Eric W.M. Heddle M.A. B.Sc.] Royal Technical College , Glasgow
