82 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
at intervals of hour, with a 2 com. aqueous solution of methylen- 
blue (BX). After several injections (3-6), the animal is dead, and the 
brain, in 2-3 parts, is placed in 10 gr. ammonium molybdate + 100 ccm. 
water + 10 drops hydrochloric acid. This fluid must first be cooled to 
zero, and the pieces are left in it at zero till next day. After being 
washed for two hours in running water, they are treated, still in the 
cold, with gradations of alcohol. The neurones and their connections 
are thus readily investigated. 
(3) Cutting-, including Imbedding and Microtomes. 
Gelatin Method for Imbedding Objects for Exhibition.* — For keep- 
ing perishable fruits, such as apples, grapes, &c., intended for lecture 
purposes, exhibitions, &c., Herr J. Wortmann recommends the use of 
gelatin to which 1 per cent, of carbolic acid has been added. The 
medium is clear and transparent as water. The specimens to be ex- 
hibited — suspended in the desired position — are immersed in the phenol- 
gelatin while the medium is hot and liquid. Fixed in this way, prepa- 
rations of healthy and diseased grapes, pears, apples, plums, &c., make 
not only excellent objects for demonstration, but are not damaged in 
transport. The method is much more effective and less troublesome 
than preservation in spirit. 
(4) Staining and Injecting. 
Methylen-Blue.j* — Mr. A. D. Morrill calls attention to a few points 
observed in the use of the methylen-blue method by the investigators at 
Woods’ Holl, which he thinks may bo of general interest. The method 
has been successfully applied during the past summer to the study of 
the nervous system of a great variety of forms. The method of ap- 
plication and strength of the solution were determined by experiment 
for each animal and tissue. During the action of the stain the animal 
or tissue was kept as nearly as possible in its normal condition. Every- 
thing seems to depend on keeping the tissue alive, and in bringing the 
stain into contact with it in a solution of a strength suitable for obtain- 
ing the best results. In some cases the abundant supply of oxygen was 
of great importance, whilst in others it seemed to make little difference. 
It was found that animals which live in the dark stain better in the 
dark than in the light. Recently caught and perfectly normal animals 
stained more satisfactorily than those which had been kept in con- 
finement for some time. For obtaining satisfactory serial sections, the 
tissues must be placed in Bethe’s fluid ; but a difference must be made 
between Vertebrates and Invertebrates, for the latter require less oxy- 
gen. Dr. Huber’s plan of placing the tissue directly in cold absolute 
alcohol on removing it from water, and changing several times for a 
period of two hours, gave good results. 
Methylen-Blue Methods.^ — Dr. A. Bethe discusses the various ways 
of fixing Ehrlich’s methylen-blue for nerve-staining. The method he 
has previously employed is probably the best, but it requires cooling 
with ice. He sought for a readily soluble combination of methylen-blue 
* Bot. Ztg., liv. (1896) pp. 337-40. f Amer. Natural., xxx. (1896) pp. 857-9. 
t Anat. Anzeig., xii. (1893) pp. 438-46. 
