255 



diifer considerably in the two cases, because the lines of evolution 

 have been so divergent. But, although the means adopted to attain 

 the end (i. e. reduction of the duplicated number of chromosomes), is 

 not by any means identical in both, the result is the same, the attain- 

 ment of cells (nuclei), in which the primitive or reduced number of 

 chromosomes is present. In the one case the reduction is associated 

 with the formation of abortive spores (pole nuclei), in the other with 

 abortive eggs, i. e. abortive gametes (polar bodies). 



Even in the steps leading to the spore-formation abortive pro- 

 ducts may be formed, as in Onychodromus grandis, where, in 

 addition to abortive spores, functionless, and therefore abortive, spore 

 daughter-nuclei obtain (Fig. 46). 



The same form is also interesting as presenting at the close of 

 the division D a number of abortive gametes, which are to be regarded 

 as in a certain sense the homologues of the "polar bodies" of Meta- 

 zoan oogenesis. Similar abortive gametes are also present at the cor- 

 responding stage in Vorticella. 



BovERi has shown that the "polar bodies" of Metazoa represent 

 abortive eggs. It has now been proved that in the Infusorian con- 

 jugation abortive spores are invariably, and abortive gametes occasion- 

 ally, formed. 



It also follows that the essential act of conjugation, apart from 

 the spore-formation and other processes leading up to the formation 

 of like gametes, is the same in both Protozoa and Metazoa^), i. e. 

 the union of two like nuclei, not as is often stated, two like half- 

 nuclei. 



Finally, from all that has been adduced in the course of the 

 discussion, it may be concluded that there is one universal law under- 

 lying all those processes (conjugation, fertilisation), which are classed 

 together as sexual in nature, and this law has been defined in the 

 preceding pages. 



Nachdruck verboten. 



Formol, or Formaldehyde? 



By Arthur Bolles Lee, Nyon, Switzerland. 



The already extensive literature which treats of the anatomical 

 uses of formaldehyde is much confused by inaccurate use of the terms 

 formol, formalin and formaldehyd. Formaldehyd is the chemical 



1) and in plants. 



