47 



puscles, but as si^aces Avithout distinct walls merely exca- 

 vated in the fundamental substance of the tissue, and stand- 

 ing in direct communication with the lymphatics ; the con- 

 nective tissue cells properly so called being contained within 

 these cavities, and taking their shape from the shape of the 

 particular part of the space in which they might happen to 

 be contained. The two methods of investigation used by 

 Recklinghausen, viz. the method of injection, and that of 

 silver impregnation, have been much assailed, but, as Dr. 

 Koster thinks, wrongly. It is by the aid of the same methods 

 that he has succeeded in demonstrating a ' plasmatic system' 

 in the umbilical cord ; and his views on the construction of 

 this system are, uj) to a certain point, the same as those in 

 Recklinghausen. As early as 1832, Fohmann^ described a 

 system of vessels in the umbilical cord, and regarded them as 

 lymphatics ; but his observations seem to have referred chiefly 

 to extravasations. 



The investigation is divided into two parts, one relating to 

 the mucous tissue itself, the other to the epithelium. In the 

 investigation of the former, three methods were adopted : 

 (1) injection; (2) silver impregnation; (3) simple examina- 

 tion of perfectly fresh specimens. 



1. The method of injection Avas thus carried out. By means 

 of a " Pravaz" syringe, a somewhat concentrated solution of 

 Prussian blue was simply forced into the denser parts of the 

 cord, not into any vessels. In this way patches an inch long 

 were injected in fresh specimens with a delicate blue network, 

 and still better results obtained by using specimens hardened 

 for some hours or days in 20 per cent, alcohol. The micro- 

 scopical examination of parts thus injected showed in the 

 deeper layers a network of intercommunication by channels 

 varying much in width. They were for the most part sj)aces 

 unequally distended in a varicose manner, sometimes lying 

 close to one another with hardly any intervening substance, 

 and in other cases connected by finer branches. No regular 

 arrangement could be made out, but the whole gave the un- 

 mistakable impression that the blue injection had found its 

 way into previously existing channels and not into mere 

 arbitrary extravasations produced by violence. This impres- 

 sion was strengthened by the number of smaller channels 

 which connected the larger spaces. In the more suiDcrficial 

 parts a similar blue network was seen (fig. 1), but the channels 

 were here narrower, and also more uniform in size ; though 

 still with sufficient varicosity of outline to show that they 

 were very greatly dilated. 



1 'Tiedemann u. Treviranus Zeitschrift,' Bd. iv, 1S32, p. 276. 



