946 



Wislar Institute" and othei- places. 1 too shall probably pass on to 

 this aninial if I have oc*casix)n to continne the present invesligations. 

 Although I was unawai-e of these investigalions on Mus norioegicus 

 albinus, I have, however, amongst n\\ material a species that is 

 rather closely i-elaled to it, namely }his rnttus — a male and a 

 female specimen, and their eleven (11) young ones; of the young 

 ones, however, only three (10, 20, and 30 days old respectively) 

 have been investigated up to now. My material consists, in addition, 

 of 58 specimens of Mus iiuiscuhis alhiims (of ages ranging from 

 24 hours to over 2 years). Among these 58 theie are several 

 lifters — thus, foi' instance, a male aiui a female, each over two 

 years old, with several generations of their progeny, 42 altogether. 

 I had also 22 specimens of Bos taiiriis — (half of them two 

 weeks old and the other half over three years — only n. trochlearis 

 and n. oculomotorins were investigated), 5 specimens of Canis 

 fmni/iaris, (the two parents and three young ones 6, 17, and 60 

 days old respectively), a number of specimens of Fe/is domestica 

 (only n. trochlearis and n. occulomotorius have been investigated 

 so far) ^). Among cold-blooded animals there were 28 toads {Bu/o 

 vulgaris) of different lengths, ranging from 1,6 to 9,8 cms. from 

 nose to tail — but the number of (hose that are near the minimum 

 and maximum dimensions is larger than those in between. 



The coluirma vertebralis with its S|)inal cord and spinal nerves 

 (even including the spinal ganglia of Bu/o, Mus musculus and Mus 

 rattus), the central nerve system with the attached sub-dural parts 

 of the spinal and cranial nerves of Canis and Felis and the sub- 

 dural parts of nil. trochleares and oculumotorii of Bos were fixed 

 in a twenty per cent formalin solution. Previous to this convenient 

 spinal ganglia and pieces of the medulla spinalis had been taken 

 out for fixation in Flemiming's liquid. The material that had been 

 fixed in Fi,kmming's liquid was imbedded in paraffin and was partly 

 cut into sections 3 — 5 n thick, which were stained with the iron- 

 alum-hematoxylin of Heidenhain and eosin. The material that had 

 been fixed in formalin was impregnated in pieces according to my 

 modifications ') of Bielschowskt's method of silver impregnation, 



1) I shall give a more detailed account of these matters in a subsequent and 

 more extensive publication. 



') Agduhr. Erik. Ueber Slückfarbung mil Bielschowskt's Silberimpragnations- 

 methode. Einige Modifikationen. Zeitschr. f. wiss. Mikrosk. u. f. mikr. Techn. 

 Bd. 34. 1917. 



