SummaryParenteral administration of Encephalitozoon cuniculi induced an antibody response within 7-11 days. Peroral administration was less effective since only 2 of 6 animals showed seroconversion; they became seropositive within 14-21 days. Sera from animals which became seropositive had high antibody titres during the whole test period.Immune sera from 3 animals were fractionated by gel filtration. With the india-ink immunoreaction test, antibodies to E. cuniculi were found only in the 7S fractions, while the indirect fluorescent-antibody test detected them in fractions I9S and 7S. The 7S fractions were identified as IgG and the 19S fractions as IgM.A program for eradication of encephalitozoonosis, based on these results, is discussed.

The histopathological features of the inner ears in a case of deafness in an old English sheepdog reveal a cochleo-saccular (Scheibe) type of degeneration. However, also the hair cells in the vestibular part of the labyrinth were reduced in number though there appeared no clinical signs or symptoms of vestibular dysfunction. The present case is the so far only known old English sheepdog with a hearing loss reported in Sweden.

LS 1727, a nitroso‐chloroethyl carbamate of 19‐nortestosterone, given intraperitoneally had a high cytostatic activity against some experimental tumours. In vitro studies showed that the tested tumours differed in their ability to hydrolyze LS 1727. The hydrolytic capacity was related to the sensitivity to treatment with LS 1727. Distribution studies with double‐labelled LS 1727 demonstrated that the chloroethyl‐part of the molecule was retained in dimethylbenz(a)anthracene‐induced mammary tumours in the rat. Our findings suggest that the antitumour activity of LS 1727 is exerted by alkylating metabolites released at hydrolysis of the compound. LS 1727 had no oral antitumour activity probably due to pre‐systemic hydrolysis. When given intravenously, hydrolysis of LS 1727 in lungs caused severe pulmonary toxicity already at low doses.