244 NOTES AND COMMENTS [october 



" localisation " of developmental processes which appears to the author 

 to bring out clearly the distinctive character of an organism as opposed 

 to an inanimate system. The first illustration given may make the 

 matter plainer. 



Some four years ago Driesch showed that if a fully-formed 

 gastrula of a sea-urchin {Sphaerechinus granularis) be halved equa- 

 torially, so that each half has half of the ectoderm and half of the 

 archenteron, both portions heal up and become spherical again, and 

 both soon show a gut divided in the normal proportions into three 

 parts. This is a simple instance of a familiar kind of phenomenon 

 which appears to the author to prove the necessity of vitalistic inter- 

 pretation. No chemico-physical interpretation will suffice. 



We cannot here summarise the author's argument, not that it is 

 particularly difficult — for Driesch's style is limpid compared with that 

 of many — but because of the difficulty of translating the terminology. 

 It may be all right in German and in Germany, but we doubt if the 

 conversion of English biologists is likely to be attained by discussions 

 on "Der primar-regulatorische Charakter der Differenzirung har- 

 monisch-aquipotentieller Systeme," and the like. The little book was 

 written in about two months; it seems to us that in this, and even 

 more in other cases, it would have been well if the author had spent 

 an equal amount of time in making the wisdom of his counsel more 

 generally available to busy biologists. 



To return for a moment to the subject-matter. The machine 

 theory of an organism is insufficient, since some of the most char- 

 acteristic vital phenomena seem to transcend the categories of 

 mechanism. And even if we come to understand a living creature as 

 we understand a steam-engine, there remains the idea behind them 

 both. Sooner or later we have to fall back upon an unknown 

 " Gesetzlichkeit." The author's contention is that there is in the 

 organism an elementary irreducible " Gesetzlichkeit." To overlook 

 this, he says, is like overlooking the spider in our science of the web. 



Morphology of the Sting in Hymenoptera. 



The embryological researches of the last twenty years seem to have 

 securely established that the stinging apparatus in ants, bees, and 

 wasps is derived in part from ventral segmental outgrowths, and in 

 part from the integumentary skeleton of certain segments. In a 

 recent paper (Zeitschr. wiss. Zool. lxvi. 1899, pp. 289-333, 2 pis.) 

 Dr. Enoch Zander has analysed the apparatus in a number of repre- 

 sentative forms, and has shown in detail how much of it is referable 

 to (the 11th and 12th) segments of the abdominal skeleton, and how 

 much to the genital appendages or gonapophyses. He shows further 



