342 BOTANICAL GAZETTE [april 



in these seeds is entirely due to the coats. The delicacy of the coat is no criterion 

 of its effect, for certainly few seed coats are more delicate than that of the upper 

 seed of the cocklebur, yet it generally secures a delay of a year or more. 



It is surprising that experimenters are so slow to see that the proper test for 

 dormancy of an embryo is to free it from incasing membranes with aseptic 

 precautions and then to subject it to germinative conditions. This treatment 

 will probably show the cause of most cases of delay to be in structures surrounding 

 the embryo. If such treatment shows real dormancy of the embryo, as in the 

 radicle of the hawthorn, 14 it is then necessary to find the particular process that 

 is delinquent. This is certainly possible in the light of the great progress that 

 is being made in studying the catalytic nature of protoplasmic activity. When 

 cases of delayed germination are investigated in this way, we may hope for prog- 



ress. 



rmancy 



germination, as it is now, more than ten years behind other phase: 



penetrates 



plant physiology. — Wm. Crocker. 



Permeability— Ruhland 1 * holds entirely untenable Overton's theory of 

 the permeability of protoplasm, both in its original form and as modified by 

 Nathansohn. In the main Ruhland offers the same sort of evidence as ha 

 Robertson 16 from the animal side. Ruhland studied the ability of vanoi: 

 organic dyes to enter the living cell. Malachite green and thionin, both almost 

 insoluble in lipoids, enter the live cells readily, while rhodamin, highly solubl 



them at all. He cites a number of other dye stufi 



where just the opposite behavior occurs to that expected by the lipoid theory 

 Both the acid and basic phthaleins are highly soluble in lipoids. The former 

 penetrate living cells readily while the latter scarcely enter at all. Riulav 

 says we have no hint of a reason for this behavior. Ruhland and Robertson 

 agree that a thin layer of lipoids often exists near the periphery of the protop asm. 

 They believe, however, that it is not continuous in any case, but only tills inttf 

 slices of the protein matter. Robertson attributes the permeable character 

 the nature of the outer, very sparingly soluble, protein layer— Wm. Crocur- 



Reproduction and stimuli.— Freund 1 7 has done a rather elaborate piece^ 

 work on the effect of external conditions upon the asexual reproduction ^o e^ 

 gonium and Haematococcus. He finds that previous culture conditions e e^ 

 very largely the effect of any reagent. Of the several methods he foun o y^ 

 ducing this response two illustrations will suffice to give an idea of the wor \ 



l « Crocker, Wm., Longevity of seeds. Box. Gazette 47'- 6 9~T 2 - j 9°9- ^^ 



'5 Ruhland, W., Beitrage zur Kenntnis der Permeabilitat der 

 Jahrb. Wiss.Bot. 46:1-54. i 9 o8. nd its relation 



16 Robertson, T. B, On the nature of the superficial layer in celIs ^ chem 4 : 

 to their permeability and to the staining of tissues by dyes. Journ. 



1-34- 1908. 



" Freund, Hans., Neue Versuche liber die Wirkung der Aussenwe 

 ungeschlechtliche Fortpflanzung der Algen. Flora 9<>:4i- Ioa IQ ° 8- 



uf <fc 



