696 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of catgut by means of heat and used for this purpose a Liebig’s bath 
filled with olive oil. Catgut left at 140° for 3-4 hours was found by 
cultivation and by experiment to be perfectly sterile. 
The author recommends two methods for preparing sterilized catgut. 
(1) Raw catgut rolled round a glass cylinder is unfatted by immersion 
in ether (ethyl) for 1-2 days. The complete absence of fat is easily 
ascertained by pouring out a little ether in a watch-glass and allowing 
it to evaporate ; if there be no residue then the fat is completely removed. 
The ether should be renewed once or twice. From the ether the cat- 
gut is removed straight away to sublimate solution 1-1000 wherein it 
remains for 24 hours, after this it is preserved in absolute alcohol. 
(2) Raw catgut having been unfatted as in the foregoing method is 
rolled in bibulous paper and heated in an oil bath for 4 hours. It is 
then placed in absolute alcohol. 
(2) Preparing- Objects. 
Simple Method of Substituting Strong Alcohol for a Watery 
Solution in the Preparation of Specimens.* — Prof. W. A. Has well 
suggests the following method : — “ Lo Bianco has in the last part of the 
‘ Mittheilungen aus der Zoologischen Station zu Neapel,’ published an 
account of the methods which he follows in preparing those marvellous 
specimens of marine invertebrates for which the station has long been 
famous all over the world. Many of the methods described have now 
been known to zoologists for some time, i. e. many of the methods of 
killing and fixing ; it is more perhaps, on account of the information 
which it gives us, as the result of a long series of trials, as to what 
reagents are best adapted to each special group, with the best modes of 
application in each case, than as giving any entirely new formulae, that 
the paper is of value. 
As is well known, marine animals of different groups require to be 
dealt with in very different ways in order that we may preserve them in 
anything approaching to their natural form. Some may be taken by 
surprise, if we may use the expression, and killed so suddenly by some 
powerful poison that they remain fixed in a life-like shape. Others 
must be narcotized or paralysed by some such reagent as chloroform, 
weak alcohol, or chloral hydrate, before the killing and fixing agent 
is used. 
Whatever be the method of killing and fixing employed, there is in 
all delicate organisms a difficulty experienced in preventing shrinkage 
during the later processes which the specimens have to undergo before 
reaching the strong alcohol stage. In the most admirably fixed speci- 
mens shrivelling will often appear when alcohol is applied. This 
difficulty is partly overcome, with great pains, by using a series of 
alcohols of ascending degrees of strength. But the result of this mode 
of procedure is not by any means always satisfactory. 
Dr. Cobb, in a paper read before this Society,! has described a 
method by which, in the case of small organisms, the shrinkage due 
to change from one fluid to another of a different density may be re- 
duced to a minimum. In his differentiator we have an instrument of 
* Proc. Linn. Soc. N. S. Wales, 2nd series, vi. (1891) pp. 433-6. 
f Op. cit., v. p. 157. See this Journal, 1890, p. 821. 
