186 



branch. This forms the last link in the chain constituting the parallel 

 vessel running along the last part of the Ileum, perhaps only one 

 centimeter from its border; but it may be three times as distant, 

 bearing one or more rows of minute arches. Thus the parallel 

 vessel is constantly drawing closer to the intestine. 



II. 



The vasa recta, extending from the parallel vessel to the in- 

 testine, present a very characteristic and striking picture near the 

 beginning of the Jejunum where they are numerous and large, rarely 

 less than four centimeters in length and perhaps five. They are, for 

 the most part, simple, but sometimes branching. Anastomoses, how- 

 ever, practically never occur between them in the mesentery. They 

 have been described as dividing at the gut to send one branch to either 

 side, and also as being so arranged that the entire vessels are distri- 

 buted alternately to one side or the other. Without saying that the 

 former disposition may not occur, I am satisfied that the latter is the 

 usual one. After the first third of the intestine is passed the vasa 

 recta are smaller and shorter but still characteristic. Towards the 

 lower end of the Ileum they are absolutely irregular. They may still 

 be seen as minute representatives of those of the other end even less 

 than one centimeter long, or this part may be supplied by little vessels 

 too ill-marked to be classified. 



Boston, March 5th 1903. 



Nachdruck verboten. 



Sulla formazione dell' aster e sulla divisione cellulare. 



Risposta al prof. Bütschli. 

 Del Dr. Andrea Giardina. 



Nel No. 17/18 (Bd. 22) di questa rivista il prof. Bütschli ha degnato 

 la mia nota sul meccanismo della divisione cellulare di alcune critiche, alle 

 quali, non per amore di polemica, ma pel solo amore della veritä, voglio 

 brevemente rispondere. E comincio tosto col riconoscere lealmente che 

 alcuni degli appunti del Bütschli hanno un giusto fondamento, quan- 

 tunque mi sembra che egli abbia ecceduto in quasi tutti i giudizii sul 

 conto mio. Se adesso rispondo perö non e tanto per protestare contro 

 questi giudizii quanto perche spero che con la discussione abbiano ad 

 esser meglio chiariti alcuni punti della questione che c'interessa. 



Convengo col Bütschli che a questo genere di speculazione non 

 e da attribuire un esagerato valore, ma credo altresi che l'utilitä che 



