Januaky 24, 1908] 



SCIENCE 



125 



by the death and casting away of a pro- 

 portion of the treated ovaries which 

 amounted to as much as 95 per cent. Simi- 

 lar fatalities resulted in other species and 

 in some all methods of treatment were 

 total failures, the ovaries being aborted 

 within a day after being treated. The 

 plants used during the last two years have 

 been growing in a state of nature on the 

 domain of the Desert Laboratory, and the 

 ripening fruits were subject to the ravages 

 of animals, with the result that the pack- 

 ages of seeds harvested represent but a 

 small fraction of the total number of 

 operations. To this destruction was added 

 the inevitable loss of many of the seedlings. 

 It is needless to say that, having used 

 such a large share of effort upon plants, to 

 which not the slightest imputation of 

 "cultivation" could be attached, precau- 

 tions of the most rigid sort will be used 

 hereafter. 



The coloring matter was injected in the 

 several types of ovaries with various re- 

 sults, according to the anatomical features 

 presented. It will be most profitable to 

 continue the discussion by the citation of 

 results with Cereus. In this species the 

 coloring fluid, fairly representing one type 

 of action of the several reagents employed, 

 was absorbed almost entirely by the inner 

 lining wall of the loculicidal cavity. The 

 strong transpiration current quickly con- 

 veys the reagent upward to where the walls 

 join and coalesce with the tissues at the 

 base of the style. Here a mass of cells a 

 centimeter in thickness was found to be so 

 thoroughly impregnated with the solution 

 as to be distinctly colored. 



The funicular stalks had also taken up 

 a large share and this had been conducted 

 out along the concave flanks and through 

 the conductive tissues as far as a mass of 

 thin-walled cells in the outer part of the 

 inner integument, being still separated 

 from the antipodal cells by several proto- 



plasts. The numerous glandular hairs on 

 the funiculi were also deeply stained, 

 probably by contact with the mass of 

 liquid poured into the cavity. The ceUs 

 surrounding the micropyle had taken up 

 a noticeable amount, probably in the same 

 manner. 



Here then is a set of mechanical condi- 

 tions under which the pollen tube carrying 

 the generative nuclei can not reach an egg 

 without passing through a deeply impreg- 

 nated tissue at the base of the pistil, com- 

 ing in contact with scores of charged cells, 

 then after entering the cavity it touches 

 and adheres to many of the impregnated 

 trichomes of the funiculi, and, lastly, in 

 reaching the egg, it must pass the endo- 

 stomal cells, also heavily laden with the 

 reagent. In the numerous anatomical ex- 

 aminations made, pollen tubes were found 

 which had become stained before reaching 

 the micropyle. In this species, therefore, 

 any alteration in the normal transmission 

 of hereditary characters might very weU 

 be ascribed to efl'ects produced in the 

 chromatin or plasma of generative nuclei 

 of the pollen. In other instances the eggs, 

 or rather the embryo-sac might be more 

 easily acted upon by an injected reagent. 

 It is to be said also that the Cereus struc- 

 tures might be affected in a different man- 

 ner by other reagents, but in all cases the 

 pollen tube would necessarily pass through 

 tissues impregnated with the reagent. 



The mechanism of the action of the 

 reagents employed is not capable of ready 

 analysis. It may be readily appreciated, 

 however, that any withdrawal of water, or 

 introduction of substance, would be fol- 

 lowed by a disturbance of the balance 

 existing among the various ions in the 

 chromatin and plasma. The slightest dis- 

 turbance of a protein, or even a modifica- 

 tion of the relative rate at which various 

 px^ocesses might be proceeding, would ac- 

 count for the prof oundest changes in quali- 



