Neuh Zentralblatt für Physiologie. 353 
cholin used. Great care was therefore exereised to proserve the 
purity of the preparations, since Modrakowski claims that even 
brief exposures to light and air alters their physiological properties. 
Our cholin salts were synthesized for us by Dr. Renshaw 
according to the method lately described by him!). Their purity was 
ascertained by chemical analysis. Some of the numerous preparations 
used were repreeipitated many times; they were tested on animals 
within twenty-four hours after they were dried for analysis. One 
product was further carefully purified according te the specific di- 
rections of Modrakowski. 
The physiologieal injeetions were made intravenously in cats 
and dogs during ether anaesthesis. The uniform result was a rapid, 
brief fall in pressure, succeeded by a more gradual return to normal, 
and not infrequently a subsequent slight rise above the normal 
level. After atropinisation the fall never took place. A typical curve 
is reproduced here. 
Even with large doses of cholin the profound depressor ef- 
fects figured by Modrakowski and others for commercial cholin 
products could never be obtained. Neither did we fail to get the 
same pieture after each of the frequently repeated injections, al- 
though Modrakowski showed in his experiments that the alleged 
contaminating substance „ist offenbar nur in ganz geringer Menge 
gegenwärtig; denn bei rasch hintereinander erfolgenden Injektionen 
vermag; die blutdrucksteigernde Cholinwirkung doch durchzudringen”. 
It should be emphasized that our animals (mostly cats) were 
not curarized°). In view of the extremely minute doses of certain 
cholin derivatives which Hunt?) has found to be effective on blood 
pressure it could not be denied that the transitory fall noted by 
us and others might be due to some contamination of this sort too 
small to be noticeable in any chemical purity analysis. We have 
attempted to answer this objection by studying the quantitative response 
to the same dose of the successive fractions of cholin salts obtained by 
erystallization of large quantities. The quantitative variations were 
inconspicuous and exelude the probability of the explanation suggested. 
A prolonged fall of pressure could never be obtained even 
with large doses of our preparations. 
The details of our studies will be published elsewhere. 
(Aus der medizinischen Universitätsklinik in Genua [.Direktor: 
Prof. Maragliano].) 
Über die Reaktion des Blutes auf Silberhydrosol. 
Von Dr. Gioacchino Breccia, Assistent. 
(Der Redaktion zugegangen am 28. Mai 1910.) 
Schon Herr Professor Axenfeld (Perugia) beobachtete eine 
fällende Wirkung des Blutes auf stark verdünntes Collargol. 
1) Journ. Amer. Chem. Soc. 1910, XXXIL, 128. 
2) Vgl. BurquetetPachon: Compt. rend. Soc. de biol. 1909, LXVII, 218. 
>) Vgl. Hunt and Taveau: Journ. of exper. Pharm. 1909, I, 308. 
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