484 ANDREW T. RASMUSSEN 



weight of each testis, were obtained. From this data the weight 

 of the testis as per cent of the reduced body weight (gross weight 

 minus gastro-intestinal contents and urine) was calculated. The 

 position of the testis was also recorded. In every case the 

 weight of each testis of the same animal was practically the 

 same. 



From about one-fourth to one-eighth of one testis (depending 

 upon its size) was fixed for eight hours in Zenker's fluid with the 

 acetic acid reduced to only four drops per 100 cc. A few whole 

 testes were also fixed in this solution and sectioned longitu- 

 dinally in order to see if the interstitial cells were equally dis- 

 tributed in the various regions of the testis at the different 

 seasons of the year. After washing in running water for an hour, 

 such issue was placed in 2 per cent potassium dichromate for 

 four and one-half days. After a second washing of two hours 

 in running water, it was dehydrated in the usual grades of alcohol 

 containing iodine, two hours with several changes being allowed 

 for each grade till 98 per cent was reached. Here only one 

 hour was allowed. From 98 per cent alcohol the tissue was 

 transferred to chloroform for one hour with several changes and 

 then to chloroform-paraffin for one hour, and finally to par- 

 affin (melting at 54°C.) for two hours or longer. The aim of this 

 rapid embedding was to preserve the lipoids. This technique 

 as well as the subsequent Weigert staining was recommended 

 by Kingsbury who has found it very useful in demonstrating 

 lipoids (Kingsbury, '11). The fixer was not sufficiently washed 

 out by this method so that it was necessary to leave the sec- 

 tions, after having been fixed on the slide, several hours in the 

 lower grades of alcohol containing iodine before they were free 

 from precipitates. 



This material was stained in ordinary hematoxylin and eosin, 

 iron hematoxylin, acid fuchsin and methyl green according 

 to the technique employed by Bensley ('11), but especially with 

 copper hematoxylin (Weigert's), the older technique of differ- 

 entiating in the potassium ferricyanide and borax mixture 

 (diluted 3 to 10 times) being employed. 



