Linkage of chloroquine resistance in Plasmodium berghei to infection of immature erythrocytes of mice.

Studies of infective potency were done to determine why chloroquine-resistant $\text{P.}$$\text{berghei}$ is an obligate parasite of immature erythrocytes. Infective potency was estimated from the length of time required for mice to develop parasitemia of 2% (delay in parasitemia). The delay in parasitemia was an inverse linear function of the logarithm of the number of parasites inoculated. A single regression line fitted the data both for susceptible and for resistant parasites, indicating identical infective potencies which, in turn, indicates that chloroquine-resistant $\text{P.}$$\text{berghei}$ selects and preferentially infects immature erythrocytes whereas it rejects mature erythrocytes.     

Multi-Sample Slippage Test for Ordered Observations

A multi-sample slippage test based on ordered observations has been given. The test statistic is based on the sum of ranks of the sample. The probability distribution of the test statistic has been worked out for small sample and it turns out to be chi-square distribution for large sample. The analytical procedure has been explained by a numerical example.