518 EXPERIMENT STATION RECORD. [Vol.40 



The greater part of the work here reported was done upon the pollen 

 mother cells of Nicotiana tabacum. In addition to this, comparative observa- 

 tions were made on a number of other plants. These observations are dis- 

 cussed at some length as regards the various changes or relations noted and 

 their probable significance. 



The existence of a form of division by furrowing in certain cells of higher 

 plants suggests the possibility of ultimately harmonizing the usual division 

 by cell plates in these forms with the division by so-called constriction in the 

 higher animals. Both lower plants and Lower animals show types of cell 

 division more or less intermediate between these two extremes. Observed 

 facts emphasize the contention that botanists have no right to consider the 

 protoplast alone as the cell, the mowing and dividing cell of the higher plants 

 rather constituting a unit comprising both protoplast ami cell wall. 



The relations of the spindle fibers to cell-plate formation and to tin- nuclei 

 favor the idea that the cell plate is primarily of nuclear origin. 



Cell division by furrowing in Magnolia, < '. II. l'u:i: i 1 mer. Jour. Hot., 5 

 {1918), No. 7, pp. 879-395, pu. 3).— Following op the work noted above, the 

 author reports a study based upon cultivated varieties "f Magnolia grown at 

 Cinchona Station, Jamaica, making use of the methods employed in the former 

 investigation. 



While in Nicotiana neither a cell plate nor u furrow can be observed to form 

 between the first and second QUClear divisions, in Magnolia the formation of 

 both these structures is initiated, thougb neither is completed before the homoe 

 otyplc karyokinesla The changes observed are described in detail with discus 

 Bion and suggestions. Evidence pointed out is though! to Indicate thai the 

 nudear membranes are Important factors in the process "i furrowing. 



Some factors affecting inulase formation in Aspergillus niger, V. H. 

 Yoi-m; {Plant World, 21 {1918), Not !,. pp. 75-87. ~>. /</>. 114-1.13).— The 

 author's study of the eff» t of age and carbohydrate nutrition on the enzym con- 

 tent of a fungus has been confined almost entirely to inulase m- produced in 

 .•l. niger. This organism produces Inulase in appreciable quantities under all 

 conditions here employed, the quantitative rate of increase culminating at the 

 period of sporulatioo and rapidly declining thereafter to zero. Thougb t; I ■ i — 

 enzym Is formed when other carbohydrates are used as the Bole source of 

 carbon, it is produced most abundantly in the presence of inulin, soluble starch 

 being next to inulin in this respect, and glucose being least efficient 



Substances closely related as to chemical structure appear to be more efficient 

 In stimulating enzym formation than are those nol closely related. The Increase 

 or decrease In the production of inulase caused by changing the amount of 

 Inulin In the culture medium Is by no means proportional to such variation. 



inulase production did not appear to he affected by glucose in the presence of 

 Inulin, nor did it appear to be in any way a starvation phenomenon. 



The biology of Oidium lactis, (J. Linossiku {Compt. Rend. Soo. BW>1. 

 [Paris), 80 {1917), No. 9. />/>. , I. Two groups of studies are briefly 



noted. The author has draw n the Conclusion that i excepting for the increase of 



some mineral substances which appear to a<t as catalyzers, exerting when pres 

 ent in very small proportion their maximum effect in the presence of different 

 nutrients which can be completely utilized) the growth of 0. lactis is propoi 

 tional to the amount of nutrient supplied thereto up to a certain point Beyond 

 this, the rate of increase of utilization diminishes in comparison with the amount 

 of nutrient supplied until a maximum point Of Utilization is reached. Beyond 



such a maximum point, injurious effects were o b s erved which were particu- 

 larly noticeable in case of nitrogenous materials, this fact recalling the afffti 

 of excess nitrogenous alimentation in case of animals. 



